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Qdot™ 565 ITK™ Carboxyl Quantum Dots (Invitrogen™)

Qdot® 565 ITK™ carboxyl quantum dots are the ideal starting material for preparing custom conjugates that require high loading of biomolecules. These materials are carboxylate functionalized and can be coupled to amine groups of proteins and modified oligonucleotides using EDC-mediated condensation. The coatings of these probes provides more binding sites than our Qdot® ITK™ amino quantum dots, but lacks PEG linkers that help to prevent non-specific interactions. These materials can be conjugated to X-PEG-amine bi-functional linkers for custom reactivity and higher specificity. Our Qdot® ITK™ carboxyl quantum dots are provided as 8 µM solutions and are available in all 9 Qdot® probe colors.

Important Features of Qdot® ITK™ Carboxyl Quantum Dots:
• Qdot® 565 ITK™ carboxyl quantum dot has emission maxima of ~565 nm
• Extremely photostable and bright fluorescence
• Efficiently excited with single-line excitation sources
• Narrow emission, large Stokes shift
• Available in multiple colors
• Ideal labeling and tracking applications


Properties of Qdot® Nanocrystals
Qdot® probes are ideal for imaging and labeling applications that require bright fluorescent signals and/or real-time tracking. Unique among fluorescent reagents, all nine available colors of Qdot® probes can be simultaneously excited with a single (UV to blue-green) light source. This property makes these reagents excellent for economical and user-friendly multiplexing applications. Qdot® labels are based on semiconductor nanotechnology and are similar in scale to moderately sized proteins.

About the Innovator’s Tool Kit Qdot® ITK™ Reagents
These Qdot® ITK™ probes are ideal for researchers who wish to prepare specific (non-stocked) conjugates for their applications and need customizable conjugation functionality.

Other Forms of Qdot® Nanocrystals are Available
In addition to the carboxyl-derivatized form, we offer Qdot® ITK™ quantum dots with amino and aliphatic hydrocarbon modifications. We’ve also developed a wide range of Qdot® nanocrystals conjugates and labeling kits. Investigate the properties of Qdot® nanocrystals or read the Molecular Probes® Handbook Section 6.6—Qdot® Nanocrystals to find out more.

For Research Use Only. Not intended for any animal or human therapeutic or diagnostic use.

5-IAF (5-iodoacetamido-fluorescein) (Thermo Scientific™)

Thermo Scientific 5-Iodoacetamido-Fluorescein (5-IAF) is a high-performance derivative of fluorescein dye, activated for easy and reliable labeling of antibodies, proteins and other molecules for use as fluorescent probes. 5-Iodoacetamido-Fluorescein is a sulfhydryl-reactive derivative of fluorescein that labels proteins and other molecules having free thiols (cysteine side chains)

Properties of 5-Iodoacetamido-Fluorescein:

• Alternative names: 5-IAF, 5-iodoacetamidofluorescein
• Chemical name: Acetamide, N-(3',6'-dihydroxy-3-oxospiro (isobenzofuran-1(3H), 9'-(9H)xanthen)-5-yl)-2-iodo
• Molecular weight: 515.26±3
• Excitation source: 488 nm spectral line, argon-ion laser
• Excitation wavelength: 494 nm
• Emission wavelength: 518 nm
• Extinction coefficient: > 80,000 M-1cm-1
• CAS #: 63368-54-7
• Solubility: Soluble in DMF; aqueous buffers at pH > 6
• Reactive groups: Iodoacetamide, reacts with sulfhydryls at pH 7.0 to 7.5

Applications:
• Label antibodies for use as immunofluorescent probes
• Label oligonucleotides for hybridization probes
• Detect proteins in gels and on Western blots

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Zenon™ Biotin-XX Mouse IgG2a Labeling Kit (Invitrogen™)

Zenon® labeling technology provides a fast, versatile, and reliable method for adding a fluorescent label to an antibody. You need only a small amount of starting material, and the method is optimized for efficient labeling of antibodies in serum, ascites fluid, or hybridoma suspensions. Antibody conjugates formed using Zenon® technology may be used in any protocol where a directly labeled primary antibody is suitable, including flow cytometry, imaging, and high-throughput applications. This exclusive Molecular Probes® Zenon® labeling technology greatly simplifies the use of multiple mouse-derived antibodies in the same staining protocol.

Important Features of Zenon® Labeling Technology:

• Labeled antibodies typically ready to use in 10 minutes
• Requires only 1–20 μg primary antibody
• Simple, no purification required
• Flexible–over 24 fluorophores plus biotin, HRP, alkaline phosphatase, and TSA to choose from
• Multiplex with other mouse monoclonal antibodies simultaneously


Save Time and Antibody
Each kit comes with affinity-purified monovalent Fab fragment of a goat anti-Fc antibody (or, in the case of the Zenon® Goat IgG Labeling Kits, a rabbit anti-Fc antibody) that has been conjugated to one of our premier Alexa Fluor® dyes or to Pacific Blue™, Pacific Orange™, fluorescein, or Texas Red®-X dyes, biotin R-phycoerythrin (R-PE), allophycocyanin (APC), HRP, or alkaline phosphatase.

Formation of the Fab–antibody complex with the Zenon® Antibody Labeling Kits is extremely fast (5 min for complex, 5 min for blocking step). And Zenon® labeling is a reliable and reproducible method, even with as low 0.4 μg in 2 μL of primary antibody. There is minimal waste of expensive or difficult-to-obtain antibodies when using the Zenon® Antibody Labeling Kits.

Preserve Primary Antibody Function and Affinities
Reactive dye labeling of primary antibodies can have unpredictable and undesirable outcomes. Among these are reduced binding affinities by label addition in the binding pocket. Zenon® antibody labeling approach, targeted to the Fc tail, avoids this concern.

Moreover the Zenon® dye- and enzyme-labeled Fab fragments have been affinity purified during their preparation to help ensure their high affinity and selectivity for the Fc portion of the corresponding primary antibody. The procedure for chemical labeling of the Fab fragments protects the Fc-binding site, resulting in more active labeling reagents.

Many Fluorophore and Enzyme Labels Available
Zenon® immunolabeling technology makes it very easy to change fluorescent color combinations or detection methodologies by simply using a different dye- or enzyme-labeled Fab fragment from our extensive selection of over 100 Zenon® Antibody Labeling Kits. If larger quantities or covalent attachment of the label is desired, see Antibody Labeling from A to Z or use our Labeling Chemistry Selection Tool for other choices.

Zenon® Technology Simplifies the Use of Multiple Antibodies of the Same Isotype in the Same Protocol
The stability of the Zenon® complex is sufficient to allow sequential (or simultaneous) labeling of different targets in cells and tissues with multiple antibody complexes. Subsequent to staining, an aldehyde-based fixation step can permanently block the transfer of Zenon® labels between different primary antibodies and will preserve the staining pattern.

We’ll Make a Custom Antibody Conjugate for You
If you can’t find what you’re looking for in our stocked list, we’ll prepare a custom antibody conjugate for you. Our custom conjugation service is efficient and confidential, and we stand by the quality of our work. We are ISO 9001:2000 certified.

For Research Use Only. Not intended for animal or human therapeutic or diagnostic use.

Related Links:

Zenon® Labeling Technology
Zenon® Technology: Versatile Reagents for Immunolabeling—Section 7.3

EZ-Link™ Micro Sulfo-NHS-Biotinylation Kit (Thermo Scientific™)

The Thermo Scientific EZ-Link Micro Sulfo-NHS-Biotinylation Kit contains reagents sufficient for 8 biotinylation reactions (e.g., 0.05–0.2 mg antibody per reaction). The EZ-Link Sulfo-NHS-Biotin reagent included in the kit is a short-chain, water-soluble biotinylation reagent used for labeling antibodies, proteins and other molecules that have primary amines.

Features of EZ-Link Sulfo-NHS-Biotin:

Protein labeling—biotinylate antibodies to facilitate immobilization, purification or detection using streptavidin resins or probes
Cell surface labeling—biotinylates only surface proteins of whole cells because the negatively charged reagent does not permeate cell membranes
Amine-reactive—reacts with primary amines (-NH2), such as lysine side-chains or the amino-termini of polypeptides
Soluble—charged sulfo-NHS group increases reagent water solubility compared to ordinary NHS-ester compounds
Irreversible—forms permanent amide bonds; spacer arm cannot be cleaved
Very short—spacer arm (total length added to target) is 13.5 angstroms; it consists of the native biotin valeric acid group only.

Sulfo-NHS-Biotin is the shortest of three very similar EZ-Link Reagents that are water-soluble, non-cleavable, and enable simple and efficient biotinylation of antibodies, proteins and any other primary amine-containing macromolecules in solution. Specific labeling of cell surface proteins is another common application for these uniquely water-soluble and membrane impermeable reagents. Differing only in their spacer arm lengths, the three Sulfo-NHS-ester reagents offer the possibility of optimizing labeling and detection experiments where steric hindrance of biotin binding is an important factor. Sulfo-NHS-Biotin is offered in several package sizes and as complete protein labeling kits.

We manufacture biotin reagents to ensure the highest possible overall product integrity, consistency and performance for the intended research applications.

N-Hydroxysulfosuccinimide (NHS) esters of biotin are the most popular type of biotinylation reagent. NHS-activated biotins react efficiently with primary amino groups (-NH2) in alkaline buffers to form stable amide bonds. Proteins (e.g., antibodies) typically have several primary amines that are available as targets for labeling, including the side chain of lysine (K) residues and the N-terminus of each polypeptide.

Varieties of biotin NHS-ester reagents differ in length, solubility, cell permeability and cleavability. Non-sulfonated NHS-biotins are cell permeable but must be dissolved in organic solvent such as DMSO or DMF. Sulfo-NHS biotins (and those with pegylated spacers) are directly water soluble but not membrane permeable. Varieties containing disulfide bonds can be cleaved using reducing agents, enabling the biotin group to be disconnected from the labeled protein.

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SiteClick™ Alexa Fluor™ 647 sDIBO Alkyne (Invitrogen™)

SiteClick labeled sDIBO alkynes for antibody labeling are optimized for easy attachment to azido modified antibodies using copper-free Click chemistry. This labeled sDIBO alkyne can be used with antibodies that have been modified using the SiteClick Antibody Azido Modification Kit or engineered to contain azido moieties. These labeled sDIBO alkynes are improved versions of our original DIBO cyclooctynes, yielding conjugates that are less "sticky" and that produce lower signal background in biological samples. This modular labeling system gives you the option to choose different fluorescent labels for your antibody and attach another molecule via streptavidin or your own molecule via amine-reactive or amine-containing moieties depending on your assay.

Learn more about SiteClick labeling technology ›

Custom SiteClick Antibody Labeling Service and sDIBO labels
If you have an antibody that is considered "difficult to label" or has lost activity after labeling using a conventional method, please contact our custom service representatives to determine whether the SiteClick Antibody Labeling Service would be right for your antibody. We offer complete custom SiteClick antibody labeling services with the option of multiple detection molecules including biotin, Alexa Fluor dyes, Qdot fluorophores, R-PE, chelates for PET imaging, and many others.

Click-iT™ Plus OPP Alexa Fluor™ 594 Protein Synthesis Assay Kit (Invitrogen™)

The Click-iT® Plus OPP Alexa Fluor® 594 Protein Synthesis Assay Kit provides a fast, sensitive, and non-radioactive method for the detection of protein synthesis using fluorescence microscopy or high-content imaging. In this assay O-propargyl-puromycin (OPP) is efficiently incorporated into newly translated proteins in complete methionine-containing media and fluorescently labeled with a bright, photostable Alexa Fluor® dye in a fast, highly-specific, and mild click reaction.

Features of the kit include:

• No media change required—works in complete, methionine-containing media, no need to remove cell media
• Multiplex-enabled—Click-iT® Plus technology retains signal from GFP and binding of fluorescent-conjugated phalloidins
• Non-radioactive—an alternative to the traditional 35S-methionine methods
• Works in vivo—published results demonstrate use in vivo for determination of protein translation

The kit contains O-propargyl-puromycin (OPP), which is an alkyne analog of puromycin (also available separately), as well as Alexa Fluor® 594 picolyl azide and all necessary reagents to perform the Click reaction. The OPP is fed to cultured cells and incorporated into proteins during active protein synthesis. Addition of the Alexa Fluor® 594 picolyl azide and the Click reaction reagents leads to a chemoselective ligation, or "click" reaction, between the picolyl azide dye and the OPP alkyne, allowing the modified proteins to be detected by imaged-based analysis.

The click reaction uses bioorthogonal (biologically unique) moieties to fluorescently label proliferating cells, helping to produce low backgrounds and high detection sensitivities. Because of the mild reaction conditions, Click-iT® Plus assays detect protein translation events while enabling preservation of cell morphology, the binding of fluorescently-labeled phalloidin, and the fluorescent signal from GFP.

Unlike 35S-methionine, used in traditional methods, OPP is not an amino acid analog, so it can be added directly to cells in complete media or used to determine protein synthesis in vivo.

The kit contains all of the components needed to label and detect the incorporated OPP in newly translated proteins in samples of adherent cells. The kit includes sufficient reagents for the labeling of 25 18 mm × 18 mm coverslips using 1 mL of reaction buffer per test.

DyLight™ 800 Maleimide (Thermo Scientific™)

Thermo Scientific DyLight 800 Sulfhydryl-Reactive Dye is a maleimide-activated derivative of high-performance DyLight 800 used to fluorescently label sulfhydryl-containing peptides, proteins and other biomolecular probes.

DyLight 800 is a near-IR fluor that is invisible to the naked eye but increases the staining options when using infrared imaging systems. DyLight 800 has spectral properties that are very similar to other near-IR dyes, including Alexa Fluor™ 790 and IRDye™ 800. The high water solubility of DyLight Fluors means that a high dye-to-protein ratio can be attained without causing precipitation of the conjugates.

Features of DyLight 800 Maleimide:

High performance—DyLight 800 replaces Alexa Fluor 800 and IRDye 800 for near-infrared staining
Specific—maleimide-activated dye labels proteins and other molecules at reduced sulfhydryls (-SH)
Efficient labeling methods—well-characterized chemistry and optimized protocols provide for reliable, high-quality labeling
Optimized antibody labeling procedure—complete protocol for IgG reduction and labeling and calculating the labeling efficiency

Applications:
• Antibody labeling for immunofluorescence applications, including immunocytochemistry (ICC), immunohistochemistry (IHC), Western blotting, and ELISA assay
• Target macromolecule labeling for in vitro and in vivo fluorescent detection strategies

DyLight 800 Sulfhydryl-Reactive Dye is activated with a maleic acid imide (maleimide) moiety to form a reactive alkylation reagent. Labeling occurs through reaction of the maleimide-activated dye with reduced sulfhydryl groups (-SH) to form stable thioether bonds. Maleimides are specific for sulfhydryl groups between pH 6.5-7.5. Learn more about maleimide chemistry.

Alexa Fluor™ 555 Azide, Triethylammonium Salt (Invitrogen™)

The orange-fluorescent Alexa Fluor® 555 azide is designed to react with alkyne-containing molecules via the fast, selective and extremely efficient copper-catalyzed “click" reaction.

Qtracker™ 655 Cell Labeling Kit (Trial Size) (Invitrogen™)

The Qtracker® 655 Cell Labeling Kit uses a custom targeting peptide to deliver far red-fluorescent Qdot® 655 probe (ex/em 405–615/655 nm) into the cytoplasm of live cells. Once inside the cells, the Qdot® 655 probe provides an intense, stable fluorescence that can be traced through several generations and is not transferred to adjacent cells in a population. This trial-size version offers a convenient introduction to the Qtracker® cell labeling technology at an affordable price.

Need a different emission spectrum or longer tracking? View our other mammalian cell tracking products.

Features of the Qtracker® Cell Labeling kits include:

• Qtracker® probes allow for continuous illumination, without photobleaching or degradation problems often associated with organic dyes
• Simple to use—add Qtracker® labeling solution to cells in serum-containing media, incubate one hour, then detect and track the cells
• Provide an intense, stable fluorescence that can be traced through several generations
• Excellent tool for long-term tracking or imaging studies of live cells, including migration, motility, morphology, and other cell function assays

The Qtracker® Cell Labeling kits use a custom targeting peptide to deliver Qdot® probes into the cytoplasm of live cells. Since the cytoplasmic delivery mechanism is not mediated by a specific enzyme, no cell-type specificity has been observed. Maximum delivery is typically accomplished in less than 1 hour.

The Qdot® probes are compatible with serum-sensitive cells. The intense fluorescence from the Qdot® probes is maintained in complex cellular environments and under various biological conditions including changes in intracellular pH, temperature, and metabolic activity.

Long-Lasting, Targeted Signal
Use of Qtracker® Cell Labeling kits results in the ability to observe labeled cells with extensive continuous illumination, without photobleaching or degradation problems often associated with organic dyes. Once inside the cells, the Qdot® probes are localized to cytoplasmic vesicles and are inherited by daughter cells for at least six generations. Fluorescence from the Qdot® probes can be detected for up to a week after delivery in some cell lines. The long-term cellular retention of the Qdot® probes results in an ideal tool for studying cell motility, migration, differentiation, morphology, and many other cellular function studies. Since the Qtracker® labels do not leak out of intact labeled cells and are not transferred to adjacent cells, the Qtracker® Cell Labeling kits result in a targeted signal.

Monitor the Signal on Multiple Platforms
Qtracker® reagent-labeled live cells can be easily monitored on a variety of platforms, including flow cytometry, fluorescence/confocal microscopy, fluorescence microplate readers, and high-content imaging systems.

Minimal Impact on Live Cells
The cytotoxicity of the materials used in Qtracker® Cell Labeling kits has been tested in a variety of cell lines including CHO, HeLa, U-118, 3T3, HUVEC, and Jurkat cells. Labeling with Qtracker® Cell Labeling kits appears to exert minimal impact on cellular surface marker expression, cell proliferation, cellular enzyme activity, and cell motility.

Useful in a Variety of Cell Tracing Studies
Post-labeling, researchers have demonstrated a wide variety of applications for Qtracker®-labeled cells, including cell co-culture and cell assembly into heterotypic assemblies, multilineage differentiation, trans-differentiation versus cell fusion, embryonic and mesenchymal stem cell tracking, and cell migration dynamics.

DyLight™ 755 Maleimide (Thermo Scientific™)

Thermo Scientific DyLight 755 Sulfhydryl-Reactive Dye is a maleimide-activated derivative of high-performance DyLight 755 used to fluorescently label sulfhydryl-containing peptides, proteins, and other biomolecular probes.

DyLight 755 is a near-IR fluor that is invisible to the naked eye but increases the staining options when using infrared imaging systems. DyLight 755 has spectral properties that are very similar to other near-IR dyes, including Alexa Fluor™ 750. The high water solubility of DyLight Fluors means that a high dye-to-protein ratio can be attained without causing precipitation of the conjugates.

Features of DyLight 755 Maleimide:

High performance—DyLight 755 replaces Alexa Fluor 755 for near-infrared staining
Specific—maleimide-activated dye labels proteins and other molecules at reduced sulfhydryls (-SH)
Efficient labeling methods—well-characterized chemistry and optimized protocols provide for reliable, high-quality labeling
Optimized antibody labeling procedure—complete protocol for IgG reduction and labeling and calculating the labeling efficiency

Applications:
• Antibody labeling for immunofluorescence applications, including immunocytochemistry (ICC), immunohistochemistry (IHC), Western blotting and ELISA assay
• Target macromolecule labeling for in vitro and in vivo fluorescent detection strategies

DyLight 755 Sulfhydryl-Reactive Dye is activated with a maleic acid imide (maleimide) moiety to form a reactive alkylation reagent. Labeling occurs through reaction of the maleimide-activated dye with reduced sulfhydryl groups (-SH) to form stable thioether bonds. Maleimides are specific for sulfhydryl groups between pH 6.5-7.5. Learn more about maleimide chemistry.

Zenon™ Alexa Fluor™ 405 Mouse IgG2b Labeling Kit (Invitrogen™)

Zenon labeling technology provides a fast, versatile and reliable method for producing antibody conjugates, even with very small (submicrogram) amounts of starting material. Antibody conjugates formed using Zenon technology may be used to stain cells in any protocol where a directly labeled primary antibody is suitable, including flow cytometry, imaging, high throughput and other applications. Moreover, this technology simplifies applications that previously were time consuming or not practical, such as the use of multiple mouse-derived antibodies in the same staining protocol.

View a selection guide for all Zenon™ antibody labeling kits and other antibody labeling products.

DyLight™ 650 Antibody Labeling Kit (Thermo Scientific™)

The Thermo Scientific DyLight 650 Antibody Labeling Kit contains an NHS ester-activated derivative of high-performance DyLight 650 used to fluorescently label antibodies and other proteins that are then used as molecular probes for cellular imaging and other fluorescence detection methods. The standard size kit contains all necessary components to perform three separate labeling reactions using 1 mg of IgG or similar quantities of other proteins—the amine-reactive DyLight 650 NHS-ester in convenient single-use vials as well as purification resin and spin columns for the preparation of ready-to-use conjugate.

DyLight 650 provides vibrant far-red fluorescence with comparable or improved performance over other dyes, including Alexa Fluor™ 647 and Cy5™ dye, for fluorescent applications. The high water solubility of DyLight Fluors means that a high dye-to-protein ratio can be attained without causing precipitation of the conjugates. DyLight 650 Amine-Reactive Dye is also available as a stand-alone reagent.

Features of DyLight 650 NHS Ester:

High performance—DyLight 650 fluoresces brighter than Alexa Fluor 647 and Cy5
Specific—NHS ester-activated dye labels proteins and other molecules at primary amines (-NH2)
Convenient kit sizes—standard and microscale sizes are offered to match your experimental needs
Optimized procedure—following the standard protocol results in antibodies with excellent dye:protein ratios and recovery rates for optimum activity and fluorescence labeling

Applications:
• Primary antibody labeling for immunofluorescence microscopy, immunohistochemistry (IHC), Western blotting or ELISA assay
• Target protein labeling for in vitro and in vivo fluorescent detection strategies

DyLight 650 Amine-Reactive Dye is activated with an N-hydroxysuccinimide (NHS) ester moiety to react with exposed N-terminal α-amino groups or the ε-amino groups of lysine residues to form stable amide bonds. Learn more about NHS ester chemistry.

Typical labeling reactions require the dye to first be dissolved in anhydrous dimethyl formamide (DMF) or another suitable organic solvent before adding a specific molar amount of dye to an amine-free buffer containing the protein to be labeled. However, the high solubility of DyLight Fluors permits protein solutions to be added directly to specific amounts of the labeling reagent. This feature allows DyLight 650 Amine-Reactive Dye to be provided in multiple formats with flexible protocols to achieve efficient degrees of labeling.

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CellVue™ Jade Cell Labeling Kit (Invitrogen™)

CellVue™ dyes are lipophilic dyes that can be used to label the cell membrane for the purpose of identifying and tracking labeled cells. Cell labeling is rapid and stable and can be combined with fluorescently labeled antibodies and other markers of cellular function for flow cytometric analysis and fluorescent microscopy. Mini CellVue™ Kits are supplied with one vial of dye stock (1 mM in ethanol) and one vial of labeling vehicle (Diluent C).

CellVue™ Jade is a green fluorescent cell labeling reagent. It is optimally excited at 478 nm and has a peak emission of 508 nm. CellVue™ Jade is compatible with most multi-color applications; however, due to similar emission properties it cannot be used in combination with FITC or Alexa Fluor™ 488 reagents.

Reported Application
Flow Cytometric Analysis, Microscopy, Immunocytochemistry, Cell Labeling

Click-iT™ Alexa Fluor™ 488 sDIBO Alkyne for Antibody Labeling (Invitrogen™)

The Click-iT Alexa Fluor 488 sDIBO Alkyne for Antibody Labeling is optimized for easy attachment to azido modified antibodies using copper-free Click chemistry. This sDIBO label can be used with antibodies that have been modified using the SiteClick Antibody Azido Modification Kit or antibodies that have been engineered to contain azido moieties. These sDIBO alkynes are improved versions of our original DIBO cyclooctynes, yielding conjugates that are less "sticky" and give lower signal background in biological samples.

This modular labeling system gives you the option to choose different fluorescent labels for your antibody and attach another molecule via streptavadin or your own molecule via amine-reactive or amine-containing moieties depending on your assay.

There are multiple Click-iT sDIBO labels to choose from:
Click-iT Alexa Fluor 488 sDIBO Alkyne for Antibody Labeling
Click-iT Alexa Fluor 555 sDIBO Alkyne for Antibody Labeling
Click-iT Alexa Fluor 647 sDIBO Alkyne for Antibody Labeling
Click-iT Biotin sDIBO Alkyne for Antibody Labeling
Click-iT Amine sDIBO Alkyne for Antibody Labeling
Click-iT SDP Ester sDIBO Alkyne for Antibody Labeling

Learn more about SiteClick labeling technology ›

Custom SiteClick Antibody Labeling Service and sDIBO labels
If you have an antibody that is considered "difficult to label" or has lost activity after labeling using a conventional method, please contact our custom service representatives to determine whether the SiteClick Antibody Labeling Service would be right for your antibody. We offer complete custom SiteClick antibody labeling services with the option of multiple detection molecules including biotin, Alexa Fluor dyes, Qdot fluorophores, R-PE, chelates for PET imaging, and many others.

SiteClick™ Antibody Azido Modification Kit (Invitrogen™)

Create a label-ready site-specific azido-modified antibody without lengthy and inefficient genetic modification using the SiteClick Antibody Azido Modification Kit. SiteClick labeling uses enzymes to specifically attach an azido moiety to the heavy chains of an IgG antibody, ensuring that the antigen binding domains remain unaltered for binding to the antigen target. This site selectivity is achieved by targeting the carbohydrate domains present on essentially all IgG antibodies regardless of isotype and host species. Once azido–modified, a variety of labeled SiteClick sDIBO alkynes are available for attachment to the antibody via Click chemistry at your choice of scale. This provides the flexibility to choose different labels for your antibody depending on your assay.

Features of the SiteClick Antibody Azido Modification Kit:
• Contains everything required to azido-modify any species or isotype of IgG antibody
• Easy-to-follow step-by-step protocol
• Highly efficient, site-specific, reproducible labeling chemistry results in high quality antibody conjugate

Learn more about SiteClick labeling technology ›

Custom SiteClick Antibody Labeling Service and sDIBO labels
If you have an antibody that is considered "difficult to label" or has lost activity after labeling using a conventional method, please contact our custom service representatives to determine whether the SiteClick Antibody Labeling Service would be right for your antibody. We offer complete custom SiteClick antibody labeling services with the option of multiple detection molecules including biotin, Alexa Fluor dyes, Qdot fluorophores, R-PE, chelates for PET imaging, and many others.

Pierce™ Streptavidin, Hydrazide-Activated (Thermo Scientific™)

Thermo Scientific Pierce Hydrazide-Activated Streptavidin conjugate include recombinant streptavidin in a purified form activated for crosslinking to carbonyl groups in a molecule.

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IANBD Amide (N,N'-Dimethyl-N-(Iodoacetyl)-N'-(7-Nitrobenz-2-Oxa-1,3-Diazol-4-yl)Ethylenediamine) (Invitrogen™)

The thiol-reactive IANBD amide can be used to create environment sensitive probes. The absorption and fluorescence emission spectra, quantum yields, and extinction coefficients of NBD conjugates are all markedly dependent on solvent. Additionally, NBD is also a function analog of the dinitrophenyl hapten, and its fluorescence is quenched upon binding to anti-dinitrophenyl (anti-DNP) antibodies.

CellTracker™ Orange CMRA Dye (Invitrogen™)

CellTracker™ Orange CMRA is a fluorescent dye well suited for monitoring cell movement or location. After loading into cells, the dye is well retained, allowing for multigenerational tracking of cellular movements. The orange excitation/emission spectra are ideal for multiplexing with green fluorescent dyes and proteins.

Need a different emission spectrum or longer tracking? View our other mammalian cell tracking products.

• Easy to use—remove medium, add dye, incubate 30 minutes, and image cells
• Fluorescent signal retention of >72 hours (typically three to six generations)
• Orange excitation/emission spectra (548/576 nm maxima) ideal for multiplexing
• Low cytotoxicity—does not affect viability or proliferation

CellTracker™ Orange CMRA fluorescent dye has been designed to freely pass through cell membranes into cells, where it is transformed into a cell-impermeant, fluorescent dye. CellTracker™ Orange CMRA dye is retained in living cells through several generations. The dye is transferred to daughter but not adjacent cells in a population. CellTracker™ Orange CMRA dye is designed to display fluorescence for at least 72 hours, and the dye exhibits ideal tracking properties: it is stable, nontoxic at working concentrations, well retained in cells, and brightly fluorescent at physiological pH. Additionally, the excitation and emission spectra of CellTracker™ Orange CMRA dye are well separated from GFP (green fluorescent protein) spectra allowing for multiplexing.

Dansyl Ethylenediamine, 5-Dimethylaminonaphthalene-1-(N-(2-Aminoethyl))sulfonamide (Invitrogen™)

The primary aliphatic amine of dansyl ethylenediamine can be reversibly coupled to aldehydes and ketones to form a Schiff base - which can be reduced to a generate stable amine derivative by sodium borohydride (NaBH4) or sodium cyanoborohydride (NaCNH3). Carboxylic acids of proteins and other water-soluble biopolymers can be coupled to this molecule in aqueous solution using water-soluble carbodiimides such as EDAC (E2247). This fluorophore is lipophilic and environmentally-sensitive.

DyLight™ 730-B1 NHS Ester (Thermo Scientific™)

Thermo Scientific DyLight near-infrared specialty dyes, comparable to Alexa Fluor and IRDye NIR dyes, can be used to label antibodies, peptides, and other proteins at primary amines. DyLight 730-B1 dye has a structure based on the benzopyrillium core, with 1 sulfonate. It has excitation and emission peaks at 734 and 755 nm, respectively (in ethanol).

General characteristics of DyLight near-infrared emitting specialty dyes:

Large selection—the largest family of dyes available for NIR fluorescence applications
NHS ester reactive group—allows immediate labeling of antibodies, proteins, peptides and other amine-containing molecules through amide bond formation
Broad spectrum of water solubilities—choose from hydrophilic to hydrophobic dyes to optimize the right dye label for the best performance in a given application
NIR dyes avoid background interference—DyLight NIR Dyes avoid fluorescence interference or quenching effects from biomolecules present in samples
Excellent signal penetration through cells and tissues—DyLight NIR Dyes provide the optimal window for excitation and emission for in vivo imaging applications

DyLight NIR Dyes are a family of labeling agents that can be used for bright fluorescence detection in cell-based imaging or in vivo imaging applications. NIR dyes can be selected based upon their characteristic excitation and emission properties or relative hydrophilicity and hydrophobicity attributes. Dyes that contain a greater number of negatively charged sulfonates generally will have greater water solubility than dyes with fewer sulfonates. More hydrophobic dyes often provide better cell penetrating ability in vivo, while more hydrophilic dyes have less nonspecific binding potential. Each dye contains an amine-reactive NHS ester for simple modification of antibodies, proteins, peptides or other biomolecules through amide bond formation. NIR dyes are best for imaging through tissues and away from indigenous fluorescent biomolecule interference or quenching. DyLight Near Infrared Dyes represent the largest selection of fluorescent labels that are commercially available.

Criteria to consider when choosing a DyLight NIR Specialty Dye
• Excitation and emission wavelengths—choose the best dye to match the excitation and emission capabilities of your instrument
• Water solubility—choose a DyLight NIR Dye based on its relative hydrophilicity, which directly correlates to the number of negatively-charged sulfonates it has on its core structure. More hydrophilic dyes are best at maintaining water solubility of a labeled antibody and limiting the nonspecific binding of the conjugate. More hydrophobic dyes often are best at penetrating tissues and cell membranes in vivo, meaning that dyes with fewer sulfonates may work best for some applications.
• DyLight Dye selection—the broad selection of NIR dyes allows a number of candidate dyes to be tested in a given application for optimal performance.

Applications:
In vivo or ex vivo imaging
• Tumor imaging with labeled peptides
• NIR fluorescence (NIRF) imaging of labeled silica nanoparticles
• NIR in vitro imaging and characterization
• Determination of thermal stability
• Cytotoxicity assays
• Molecular imaging
• UV-VIS-NIR spectroscopy
• Fluorescence correlation spectroscopy
• MRI applications
• DNA sequencing
• Primer labeling for PCR
• 2-D gel electrophoresis
• Flow cytometry/fluorescence-activated cell sorting (FACS)
• Laser scanning confocal microscopy

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DyLight™ 747-B1 NHS Ester

Click-IT™ ManNAz Metabolic Glycoprotein Labeling Reagent (tetraacetylated N-Azidoacetyl-D-Mannosamine) (Invitrogen™)

The Click-iT® ManNAz metabolic glycoprotein labeling reagent provides the first part of a simple and robust two-step technique to identify and characterize cell surface sialic acid-containing glycoproteins. In step one, cultured cells are incubated with the azide-modified mannosamine (ManNAz). The azido-sugar is metabolically incorporated into cell surface sialic acid-containing glycoproteins through the permissive nature of the oligosaccharide biosynthesis pathway,. In step two, via the chemoselective ligation or click reaction between an azide and an alkyne, the azido-labeled glycoproteins can then be detected with a Click-iT® Glycoprotein Detection kit for gels (TAMRA or Dapoxyl® alkyne) or Western blots (biotin alkyne). These Click-iT® products are compatible with LC-MS⁄MS and Multiplexed Proteomics™ technologies for in-depth analyses of the glycoproteome.

5-TAMRA (5-Carboxytetramethylrhodamine), single isomer (Invitrogen™)

Tetramethylrhodamine (TMR, TRITC) has been a widely used fluorophore for preparing bioconjugates, especially fluorescent antibody and avidin derivatives used in immunochemistry. Under the name TAMRA, the carboxylic acid of 5-TAMRA has also achieved prominence as a dye for oligonucleotide labeling and automated DNA sequencing applications.

Biotin-HRP (biotinylated peroxidase) (Invitrogen™)

Reactivity: Reacts with streptavidin and avidin conjugates.

EZ-Link™ Iodoacetyl-LC-Biotin (Thermo Scientific™)

Thermo Scientific EZ-Link Iodoacetyl-LC-Biotin is a mid-length, haloacetyl-activated, sulfhydryl-reactive biotinylation reagent that forms stable, irreversible thioether bonds at alkaline pH.

Features of EZ-Link Iodoacetyl-LC-Biotin:

Protein labeling—biotinylate antibodies or other proteins for use in protein methods
Membrane-permeable—can be used to label inside cells (intracellular)
Thiol-reactive—reacts with sulfhydryls (-SH), such as the side-chain of cysteine (C)
Iodoacetyl-activated—perform reactions in the dark at pH 7.5 to 8.5 in Tris or borate buffer
Irreversible—forms permanent thioether bonds; spacer arm cannot be cleaved
Solubility—must be dissolved in DMSO or DMF before further dilution in aqueous buffers
Medium length—spacer arm (total length added to target) is 27.1 angstroms; contains hexylenediamine extension

Iodoacetyl-LC-Biotin is a haloacetyl-biotin compound for labeling protein cysteines and other molecules that contain sulfhydryl groups. This reagent specifically reacts with reduced thiols (-SH) in alkaline buffers to form permanent (irreversible) thioether bonds. The unique feature of Iodoacetyl-LC-Biotin is its extended yet chemically simple hexylenediamine spacer arm.

We manufacture biotin reagents to ensure the highest possible overall product integrity, consistency and performance for the intended research applications.

Biotinylation reagents differ in reactivity, length, solubility, cell permeability and cleavability. Three types of sulfhydryl-reactive compounds are available: maleimido, iodoacetyl and pyridyldithiol. Iodoacetyl reagents specifically react with sulfhydryl groups (-SH) at pH 8.3 to form permanent thioether bonds.

In proteins, sulfhydryls exist where there are cysteine (C) residues. Cystine disulfide bonds must be reduced to make sulfhydryl groups available for labeling. Hinge-region disulfide bridges of antibodies can be selectively reduced to make functional half-antibodies that can be labeled.

Applications:
• Electron microscopy studies on spatial relationships between proteins (Ref.1)
• Localizing the SH1 thiol of the myosin head using avidin-biotin complexes in electron microscopy (Ref.2)

Oregon Green™ 488 Maleimide (Invitrogen™)

The thiol reactive Oregon Green® 488 maleimide can be used to can be used to create green fluorescent bioconjugates with excitation/emission maxima ~496/524 nm.
This fluorinated analog of fluorescein overcomes some of the key limitations of fluorescein, including greater photostability and a lower pKa (pKa ~ 4.7 versus 6.4 for fluorescein), making its fluorescence essentially pH insensitive in the physiological pH range.

Alexa Fluor™ 488 TFP ester (Invitrogen™)

Alexa Fluor® dyes are reactive molecules that can be used to add a fluorescent label to the primary amines (R-NH2) of proteins, amine-modified oligonucleotides, and other amine-containing molecules. The resulting Alexa Fluor® conjugates exhibit brighter fluorescence and greater photostability than the conjugates of other spectrally similar fluorophores. Alexa Fluor® 488 TFP ester produces a conjugate with excitation/emission of 495/515 nm that is spectrally similar to fluorescein (FITC) and Cy2 conjugates.

Alexa Fluor® dyes are available with fluorescence emissions that span the visible and near-infrared spectrum (see The Alexa Fluor® Dye Series—Note 1.1 in The Molecular Probes® Handbook) and provide the unique combination of water solubility and pH insensitivity between pH 4 and 10 for compatibility in diverse biological environments.

TFP (tetrafluorophenyl) esters are an improvement over the succinimidyl ester (SE or NHS-ester) chemistry typically used to attach fluorophores or haptens to the primary amines of biomolecules. Both reactive chemistries produce the same strong amide bond between the dye or hapten and the compound of interest, but TFP esters are less susceptible to spontaneous hydrolysis during conjugation reactions. Alexa Fluor® TFP esters are stable for several hours at the basic pH typically used for reactions–far outlasting succinimidyl esters.

Typical Conjugation Reaction
You can conjugate amine-reactive reagents with virtually any protein or peptide; the provided protocol is optimized for IgG antibodies. You may scale the reaction for any amount of protein, but the concentration of the protein should be at least 2 mg/mL for optimal results. We recommend trying three different degrees of labeling, using three different molar ratios of the reactive reagent to protein.

The Alexa Fluor® TFP ester is typically dissolved in high-quality, anhydrous dimethylsulfoxide (DMSO) (D12345) , and the reaction is carried out in 0.1–0.2 M sodium bicarbonate buffer, pH 8.3, at room temperature for 1 hour. Because the pKa of the terminal amine is lower than that of the lysine epsilon-amino group, you may achieve more selective labeling of the amine terminus using a buffer closer to neutral pH.

Conjugate Purification
Labeled antibodies are typically separated from free Alexa Fluor® dye using a gel filtration column, such as Sephadex™ G-25, BioGel® P-30, or equivalent. For much larger or smaller proteins, select a gel filtration media with an appropriate molecular weight cut-off or purify by dialysis.

Learn More About Protein and Antibody Labeling
We offer a wide selection of Molecular Probes® antibody and protein labeling kits to fit your starting material and your experimental setup. See Antibody Labeling from A to Z or use our Labeling Chemistry Selection Tool for other choices. To learn more about our labeling kits, read Kits for Labeling Proteins and Nucleic Acids—Section 1.2 in The Molecular Probes® Handbook.

We’ll Make a Custom Conjugate for You
If you can’t find what you’re looking for in our online catalog, we’ll prepare a custom antibody or protein conjugate for you. Our custom conjugation service is efficient and confidential, and we are ISO 9001:2000 certified.

Fluorescein-5-Maleimide (Invitrogen™)

Searching for superior alternatives to fluorescein? Our Alexa Fluor Dye Series offers everything you're looking for and more.

Alexa Fluor™ 488 C5 Maleimide (Invitrogen™)

Alexa Fluor® 488 is a bright, green fluorescent dye with excitation ideally suited to the 488 nm laser line. Used for stable signal generation in imaging and flow cytometry, Alexa Fluor® 488 dye is water soluble and pH-insensitive from pH 4 to pH 10. In addition to reactive dye formulations, we offer Alexa Fluor® 488 dye conjugated to a variety of antibodies, peptides, proteins, tracers, and amplification substrates optimized for cellular labeling and detection (learn more).

The maleimide derivative of Alexa Fluor® 488 is the most popular tool for conjugating the dye to a thiol group on a protein, oligonucleotide thiophosphate, or low molecular weight ligand. The resulting Alexa Fluor® 488 conjugates exhibit brighter fluorescence and greater photostability than the conjugates of other spectrally similar fluorophores.

Detailed information about this AlexaFluor® maleimide:

Fluorophore label: Alexa Fluor® 488 dye
Reactive group: maleimide
Reactivity: thiol groups on proteins and ligands, oligonucleotide thiophosphates
Ex/Em of the conjugate: 493/516 nm
Extinction coefficient: 72,000 cm-1M-1
Spectrally similar dyes: Fluorescein (FITC), Cy®2
Molecular weight: 720.66

Typical Conjugation Reaction
The protein should be dissolved at a concentration of 50-100 µM in a suitable buffer (10-100 mM phosphate, Tris, or HEPES) at pH 7.0-7.5. In this pH range, the protein thiol groups are sufficiently nucleophilic that they react almost exclusively with the reagent in the presence of the more numerous protein amine groups, which are protonated and relatively unreactive. We recommend reducing any disulfide bonds at this point using a 10-fold molar excess of reducing agent such as DTT or TCEP. Excess DTT must be removed by dialysis and subsequent thiol-modification should be carried out under oxygen-free conditions to prevent reformation of the disulfide bonds; these precautions are not necessary when using TCEP prior to maleimide conjugation.

The Alexa Fluor® maleimide is typically dissolved in high-quality anhydrous dimethylsulfoxide (DMSO) at a concentration of 1-10 mM immediately prior to use, and stock solutions should be protected from light as much as possible. Generally, this stock solution is added to the protein solution dropwise while stirring to produce approximately 10-20 moles of reagent per mole of protein, and the reaction is allowed to proceed at room temperature for 2 hours or at 4°C overnight, protected from light. Any unreacted thiol-reactive reagent can be consumed by adding excess glutathione, mercaptoethanol, or other soluble low molecular weight thiol.

Conjugate Purification
Labeled antibodies are typically separated from free Alexa Fluor® dye using a gel filtration column, such as Sephadex™ G-25, BioGel® P-30, or equivalent. For much larger or smaller proteins, select a gel filtration media with an appropriate molecular weight cut-off or purify by dialysis. We offer several purification kits optimized for different quantities of antibody conjugate:
Antibody Conjugate Purification Kit for 0.5-1 mg (A33086)
Antibody Conjugate Purification Kit for 20-50 µg (A33087)
Antibody Conjugate Purification kit for 50-100 µg (A33088)

Learn More About Protein and Antibody Labeling
We offer a wide selection of Molecular Probes® antibody and protein labeling kits to fit your starting material and your experimental setup. See our Antibody Labeling kits or use our Labeling Chemistry Selection Tool for other choices. To learn more about our labeling kits, read Kits for Labeling Proteins and Nucleic Acids—Section 1.2 in The Molecular Probes® Handbook.

We’ll Make a Custom Conjugate for You
If you can’t find what you’re looking for in our online catalog, we’ll prepare a custom antibody or protein conjugate for you. Our custom conjugation service is efficient and confidential, and we stand by the quality of our work. We are ISO 9001:2000 certified.

5-CR 6G, SE (5-Carboxyrhodamine 6G, Succinimidyl Ester), single isomer (Invitrogen™)

The amine-reactive form of 5-CR 6G is used for oligonucleotide labeling and automated DNA sequencing applications. Conjugates of this dye have longer-wavelength spectra than the spectra of Lisaamine™ rhodamine B conjugates, but somewhat shorter-wavelength spectra than those of Texas Red® conjugates.

Click-IT™ Fucose Alkyne (Invitrogen™)

Identify and characterize fucosylated proteins with Click-iT® fucose alkyne using the powerful click chemistry, a simple and robust two-step labeling and detection technique. In step one, the alkyne-containing biomolecule is fed to cells or animals and actively incorporated into proteins. Unlike other labels such as biotin or a fluorescent dye, the alkyne-tag is small enough that the tagged molecule is an acceptable substrate for the enzymes that incorporate this building block into proteins. Detection utilizes the chemoselective ligation or “click" reaction between an azide and an alkyne where the modified protein is detected with the corresponding azide-containing dye or hapten using either the Click-iT® Cell Reaction Buffer Kit or the Click-iT® Protein Buffer Kit. With the Click-iT® Cell Reaction Buffer Kit, cells can be analyzed by fluorescence microscopy, flow cytometry or high-content imaging and analysis (HCS) together with other biomarkers of interest for content and context rich results. With the Click-iT® Protein Reaction Buffer Kit, achieve detection sensitivity in 1-D gels and western blots in the low femtomole range or perform LC-MS⁄MS and MALDI MS analysis.

SiteClick™ Qdot™ 705 Antibody Labeling Kit (Invitrogen™)

Create a perfectly labeled antibody with the SiteClick™ Qdot® 705 Antibody Labeling Kit. This kit replaces the conventional Qdot® 705 Antibody Conjugation Kit (Q22061MP). Unlike the conventional amine-thiol crosslinker method, SiteClick™ labeling specifically attaches the label to the heavy chains of an IgG antibody, ensuring that the antigen-binding domains remain available for binding to your antigen target. This site selectivity is achieved by targeting the carbohydrate domains present on essentially all IgG antibodies regardless of isotype and host species. In addition, no harsh reduction steps are required, and the labeling is consistent and reproducible each time it is performed. Depending upon the label, the resulting SiteClick™ -labeled antibody can be used in flow cytometry, fluorescence imaging, or Western blot detection.

Important Features of the SiteClick™ Qdot® 705 Antibody Labeling Kit:

• Contains everything required to label 100 µg of IgG antibody
• Easy to follow step-by-step protocol
• Highly efficient, site-specific, reproducible labeling chemistry results in high quality antibody conjugate.
• Qdot® 705 labels can be used in confocal or traditional fluorescence microscopy.
• In flow cytometry, Qdot® 705 can be excited by the 488 nm line of the argon-ion laser, or alternatively via excitation at 405 nm. This is true of all Qdot® fluorophores.

Qdot® Fluorophores are Our Brightest Labels
Antibody conjugates made with Qdot® fluorophores produce fluorescence output that surpasses that of traditional organic dyes. Paired with the correct optical filters, Qdot® nanocrystals are as much as 50 times brighter. Read more about Qdot® nanocrystals or review additional product details in Qdot® Nanocrystals—Section 6.6 in the Molecular Probes® Handbook.

Learn More About Protein and Antibody Labeling
We offer a wide selection of Molecular Probes® antibody and protein labeling kits (see Antibody Labeling from A to Z). To learn more about our various kits, read Kits for Labeling Proteins and Nucleic Acids—Section 1.2 in the Molecular Probes® Handbook.

Custom SiteClick™ Antibody Labeling Services
If you have an antibody that is considered "difficult to label" or has lost activity after labeling using a conventional method, please contact our custom service representatives to determine whether the SiteClick™ Antibody Labeling Service would be right for your antibody. We offer complete custom SiteClick™ antibody labeling services with the option of multiple detection molecules including biotin, Alexa Fluor® dyes, Qdot® fluorophores, R-PE, and others.

5-FAM, SE (5-Carboxyfluorescein, Succinimidyl Ester), single isomer (Invitrogen™)

Searching for superior alternatives to fluorescein? Our Alexa Fluor Dye Series offers everything you're looking for and more.

QSY™ 9 C5-Maleimide (Invitrogen™)

The thiol-reactive quencher, QSY® 9 succinimidyl ester has a broad and intense visible absorption (~560 nm) but no fluorescence making it useful as an acceptor in fluorescence resonance energy transfer (FRET) applications.

Alexa Fluor™ 594 Alkyne (Alexa Fluor™ 594 Carboxamido-(5-(and 6-)Propargyl), Bis(Triethylammonium Salt)), mixed isomers (Invitrogen™)

The red-fluorescent Alexa Fluor® 594 alkyne can be reacted with azides via a copper-catalyzed click reaction. Click chemistry describes a class of chemical reactions that use bio-orthogonal or biologically unique moities to label and detect a molecule of interest using a two-step procedure. The two-step reaction procedure involves a copper-catalyzed triazole formation of an azide and an alkyne. Click reactions have several characteristics: the reaction between the detection moieties is efficient; no extreme temperatures or solvents are required; the reaction product is stable; the components of the reaction are bioinert; and perhaps most importantly, no side reactions occur – the label and detection tags react selectively and specifically with one another. Unlike traditional chemical reactions utilizing succinimidyl esters or maleimides that target amines and sulfhydryls – functional groups that are not unique – click chemistry-labeled molecules can be applied to complex biological samples and be detected with unprecedented sensitivity due to extremely low background.

BODIPY™ FL EDA, 4,4-Difluoro-5,7-Dimethyl-4-Bora-3a,4a-Diaza-s-Indacene-3-Propionyl Ethylenediamine, Hydrochloride (Invitrogen™)

BODIPY® FL EDA can be reversibly coupled to aldehydes and ketones to form a Schiff base - which can be reduced to a generate stable amine derivative by sodium borohydride (NaBH4) or sodium cyanoborohydride (NaCNH3). Carboxylic acids of proteins and other water-soluble biopolymers can be coupled to this molecule in aqueous solution using water-soluble carbodiimides such as EDAC (E2247).

Texas Red™ Cadaverine (Texas Red™ C5) (Invitrogen™)

The primary aliphatic amine of the red-fluorescent Texas Red® cadaverine (Texas Red® C5) can be reversibly coupled to aldehydes and ketones to form a Schiff base - which can be reduced to a stable amine derivative by sodium borohydride (NaBH4) or sodium cyanoborohydride (NaCNH3) to form new biotinylated probes. Carboxylic acids of proteins and other water-soluble biopolymers can be coupled to this molecule in aqueous solution using water-soluble carbodiimides such as EDAC (E2247).

Zenon™ Alexa Fluor™ 594 Human IgG Labeling Kit (Invitrogen™)

Zenon® labeling technology provides a fast, versatile, and reliable method for adding a fluorescent label to an antibody. You need only a small amount of starting material, and the method is optimized for efficient labeling of antibodies in serum, ascites fluid, or hybridoma suspensions. Antibody conjugates formed using Zenon® technology may be used in any protocol where a directly labeled primary antibody is suitable, including flow cytometry, imaging, and high-throughput applications. This exclusive Molecular Probes® Zenon® labeling technology greatly simplifies the use of multiple mouse-derived antibodies in the same staining protocol.

Important Features of Zenon® Labeling Technology:

• Labeled antibodies typically ready to use in 10 minutes
• Requires only 1–20 μg primary antibody
• Simple, no purification required
• Flexible–over 24 fluorophores plus biotin, HRP, alkaline phosphatase, and TSA to choose from
• Multiplex with other mouse monoclonal antibodies simultaneously


Save Time and Antibody
Each kit comes with affinity-purified monovalent Fab fragment of a goat anti-Fc antibody (or, in the case of the Zenon® Goat IgG Labeling Kits, a rabbit anti-Fc antibody) that has been conjugated to one of our premier Alexa Fluor® dyes or to Pacific Blue™, Pacific Orange™, fluorescein, or Texas Red®-X dyes, biotin R-phycoerythrin (R-PE), allophycocyanin (APC), HRP, or alkaline phosphatase.

Formation of the Fab–antibody complex with the Zenon® Antibody Labeling Kits is extremely fast (5 min for complex, 5 min for blocking step). And Zenon® labeling is a reliable and reproducible method, even with as low 0.4 μg in 2 μL of primary antibody. There is minimal waste of expensive or difficult-to-obtain antibodies when using the Zenon® Antibody Labeling Kits.

Preserve Primary Antibody Function and Affinities
Reactive dye labeling of primary antibodies can have unpredictable and undesirable outcomes. Among these are reduced binding affinities by label addition in the binding pocket. Zenon® antibody labeling approach, targeted to the Fc tail, avoids this concern.

Moreover the Zenon® dye- and enzyme-labeled Fab fragments have been affinity purified during their preparation to help ensure their high affinity and selectivity for the Fc portion of the corresponding primary antibody. The procedure for chemical labeling of the Fab fragments protects the Fc-binding site, resulting in more active labeling reagents.

Many Fluorophore and Enzyme Labels Available
Zenon® immunolabeling technology makes it very easy to change fluorescent color combinations or detection methodologies by simply using a different dye- or enzyme-labeled Fab fragment from our extensive selection of over 100 Zenon® Antibody Labeling Kits. If larger quantities or covalent attachment of the label is desired, see Antibody Labeling from A to Z or use our Labeling Chemistry Selection Tool for other choices.

Zenon® Technology Simplifies the Use of Multiple Antibodies of the Same Isotype in the Same Protocol
The stability of the Zenon® complex is sufficient to allow sequential (or simultaneous) labeling of different targets in cells and tissues with multiple antibody complexes. Subsequent to staining, an aldehyde-based fixation step can permanently block the transfer of Zenon® labels between different primary antibodies and will preserve the staining pattern.

We’ll Make a Custom Antibody Conjugate for You
If you can’t find what you’re looking for in our stocked list, we’ll prepare a custom antibody conjugate for you. Our custom conjugation service is efficient and confidential, and we stand by the quality of our work. We are ISO 9001:2000 certified.

For Research Use Only. Not intended for animal or human therapeutic or diagnostic use.

Related Links:

Zenon® Labeling Technology
Zenon® Technology: Versatile Reagents for Immunolabeling—Section 7.3

Qtracker™ 800 Vascular Labels (Invitrogen™)

Qtracker® non-targeted quantum dots are designed to be injected into the tail vein of mice for the study of vascular structure using small animal in vivo imaging (SAIVI) techniques. These nanocrystals exhibit intense fluorescence with red-shifted emission for increased tissue penetration, and have a PEG surface coating specially developed to minimize nonspecific interactions and reduce immune response by the tissue. Because the PEG surface coating does not contain reactive functional groups, the Qtracker® non-targeted quantum dots are retained in circulation longer and can be imaged for up to 3 hours with a single injection or for longer periods of time with additional injections.

Need a different emission spectrum or longer tracking? View our other mammalian cell tracking products.

Key Attributes:

Qtracker® 800 label has Ex/Em (405-760/800) nm
Designed for small animal in vivo imaging
Introduced via tail vein injection, can be imaged for up to 3 hours after injection
Available in four colors—565 nm, 655 nm, 705 nm, or 800 nm emission

Read more about SAIVI and about applications for Qdot® nanocrystals.

For Research Use Only. Not intended for any animal or human therapeutic or diagnostic use.

Zenon™ Alexa Fluor™ 555 Mouse IgG2a Labeling Kit (Invitrogen™)

Zenon® labeling technology provides a fast, versatile, and reliable method for adding a fluorescent label to an antibody. You need only a small amount of starting material, and the method is optimized for efficient labeling of antibodies in serum, ascites fluid, or hybridoma suspensions. Antibody conjugates formed using Zenon® technology may be used in any protocol where a directly labeled primary antibody is suitable, including flow cytometry, imaging, and high-throughput applications. This exclusive Molecular Probes® Zenon® labeling technology greatly simplifies the use of multiple mouse-derived antibodies in the same staining protocol.

Important Features of Zenon® Labeling Technology:

• Labeled antibodies typically ready to use in 10 minutes
• Requires only 1–20 μg primary antibody
• Simple, no purification required
• Flexible–over 24 fluorophores plus biotin, HRP, alkaline phosphatase, and TSA to choose from
• Multiplex with other mouse monoclonal antibodies simultaneously


Save Time and Antibody
Each kit comes with affinity-purified monovalent Fab fragment of a goat anti-Fc antibody (or, in the case of the Zenon® Goat IgG Labeling Kits, a rabbit anti-Fc antibody) that has been conjugated to one of our premier Alexa Fluor® dyes or to Pacific Blue™, Pacific Orange™, fluorescein, or Texas Red®-X dyes, biotin R-phycoerythrin (R-PE), allophycocyanin (APC), HRP, or alkaline phosphatase.

Formation of the Fab–antibody complex with the Zenon® Antibody Labeling Kits is extremely fast (5 min for complex, 5 min for blocking step). And Zenon® labeling is a reliable and reproducible method, even with as low 0.4 μg in 2 μL of primary antibody. There is minimal waste of expensive or difficult-to-obtain antibodies when using the Zenon® Antibody Labeling Kits.

Preserve Primary Antibody Function and Affinities
Reactive dye labeling of primary antibodies can have unpredictable and undesirable outcomes. Among these are reduced binding affinities by label addition in the binding pocket. Zenon® antibody labeling approach, targeted to the Fc tail, avoids this concern.

Moreover the Zenon® dye- and enzyme-labeled Fab fragments have been affinity purified during their preparation to help ensure their high affinity and selectivity for the Fc portion of the corresponding primary antibody. The procedure for chemical labeling of the Fab fragments protects the Fc-binding site, resulting in more active labeling reagents.

Many Fluorophore and Enzyme Labels Available
Zenon® immunolabeling technology makes it very easy to change fluorescent color combinations or detection methodologies by simply using a different dye- or enzyme-labeled Fab fragment from our extensive selection of over 100 Zenon® Antibody Labeling Kits. If larger quantities or covalent attachment of the label is desired, see Antibody Labeling from A to Z or use our Labeling Chemistry Selection Tool for other choices.

Zenon® Technology Simplifies the Use of Multiple Antibodies of the Same Isotype in the Same Protocol
The stability of the Zenon® complex is sufficient to allow sequential (or simultaneous) labeling of different targets in cells and tissues with multiple antibody complexes. Subsequent to staining, an aldehyde-based fixation step can permanently block the transfer of Zenon® labels between different primary antibodies and will preserve the staining pattern.

We’ll Make a Custom Antibody Conjugate for You
If you can’t find what you’re looking for in our stocked list, we’ll prepare a custom antibody conjugate for you. Our custom conjugation service is efficient and confidential, and we stand by the quality of our work. We are ISO 9001:2000 certified.

For Research Use Only. Not intended for animal or human therapeutic or diagnostic use.

Related Links:

Zenon® Labeling Technology
Zenon® Technology: Versatile Reagents for Immunolabeling—Section 7.3

DyLight™ 550-2xPEG Maleimide (Thermo Scientific™)

Thermo Scientific DyLight 550-2xPEG Sulfhydryl-Reactive Dye is a maleimide-activated derivative of our high-performance DyLight 550 Dye used to fluorescently label cysteine-containing peptides, proteins or other biomolecular probes.

The DyLight 550-2xPEG Dye contains 2 polyethylene glycol (PEG) chains that are non-toxic, enhance fluorescence, and reduce nonspecific binding of conjugates made with them. Conjugates made with DyLight 550-2xPEG Dye can be used as molecular probes for cellular imaging, flow cytometry, and other fluorescence detection methods. The PEG chains also improve solubility of the dyes and labeled molecules in aqueous solution, aid in cell permeability, and improve tissue retention.

Features of DyLight 550-2xPEG Maleimide:

High fluorescence intensity—significantly brighter fluorescence than Alexa Fluor™ 555
PEGylated—improves solubility in aqueous solution and aids in cell permeability
Specific—maleimide-activated dye labels proteins and other molecules at reduced sulfhydryls (-SH)

Applications:
• Fluorescence microscopy
In vivo or ex vivo imaging
• Cell-based assays
• Flow cytometry/fluorescence-activated cell sorting (FACS)

DyLight 550-2xPEG Sulfhydryl-Reactive Dye is activated with a maleic acid imide (maleimide) moiety to form a reactive alkylation reagent. Labeling occurs through reaction of the maleimide-activated dye with reduced sulfhydryl groups (-SH) to form stable thioether bonds. Maleimides are specific for sulfhydryl groups between pH 6.5-7.5. Learn more about maleimide chemistry.

Click-iT™ Alexa Fluor™ 647 sDIBO Alkyne (Invitrogen™)

Click-iT Alexa Fluor 647 sDIBO Alkyne reacts with azides via a copper-free Click chemistry reaction to produce fluorescent Alexa Fluor 647 bioconjugates. sDIBO alkynes are improved versions of our original DIBO cyclooctynes, yielding conjugates that are less “sticky” and give lower signal background in biological samples. Copper-free Click bio-conjugation reactions are ideal for surface labeling of live cells and also minimize damage to enzymes and fluorescent proteins like GFP or R-PE. Macromolecules that have been azide-modified enzymatically, chemically, or metabolically can be now be labeled easily, yielding more soluble bioconjugates with improved biological labeling utility.

• More soluble than DIBO cyclooctynes leading to more soluble conjugates
• Minimal background potential in cells and tissues compared to original DIBO cycloctynes

Learn more about Alexa Fluor dyes ›

Alexa Fluor™ 546 Protein Labeling Kit (Invitrogen™)

Molecular Probes® Protein Labeling Kits provide a convenient means for attaching a fluorescent label (or biotin) to an antibody (or a protein larger than 40 kDa). Conjugates are ideal for multiple applications, including flow cytometry, fluorescent microscopy, immunohistochemistry, primary detection, ELISAs, immunocytochemistry, FISH, and more. Kits are available in 12 Alexa Fluor® dye colors, biotin, the hapten Oregon Green® 488, fluorescein EX, and Texas Red® dye. Each kit provides the components needed to perform three protein conjugations and purifications.

Important Features of Protein Labeling Kits:

• Labeled proteins typically ready to use in 2 hr (~30 min hands-on time)
• Designed to label 1 mg of IgG
• Simple protocol — react, separate, use
• Stabilizing proteins must be removed from the sample before labeling


The Benefits of Alexa Fluor® Dyes
Compared to traditional dyes, Alexa Fluor® dyes are brighter, more photostable, and more pH resistant between pH 4 and 10. And generally when using Alexa Fluor® dyes, higher degrees of labeling can be achieved without intramolecular quenching. For details see Alexa Fluor® Dyes Spanning the Visible and Infrared Spectrum—Section 1.3.

Learn More About Protein and Antibody Labeling
We offer a wide selection of Molecular Probes® antibody and protein labeling kits to fit your starting material and your experimental setup. See Antibody Labeling from A to Z or use our Labeling Chemistry Selection Tool for other choices. To learn more about our various kits read Kits for Labeling Proteins and Nucleic Acids—Section 1.2 in the Molecular Probes® Handbook.

We’ll Make a Custom Antibody Conjugate for You
If you can’t find what you’re looking for in our stocked list, we’ll prepare a custom antibody conjugate for you. Our custom conjugation service is efficient and confidential, and we stand by the quality of our work. We are ISO 9001:2000 certified.

For Research Use Only. Not intended for animal or human therapeutic or diagnostic use.

Alexa Fluor™ 790 NHS Ester (Succinimidyl Ester) (Invitrogen™)

Alexa Fluor® 790 is a bright and photostable near-IR dye that is spectrally similar to indocyanine green (ICG) and the IRDye® 800 dye. Used for stable signal generation in imaging and flow cytometry, Alexa Fluor® 790 dye is water soluble and pH-insensitive from pH 4 to pH 10. Fluorescence of this long-wavelength Alexa Fluor® dye is not visible to the human eye but is readily detected by most imaging systems. As the longest-wavelength Alexa Fluor® dye, the emission is well separated from commonly used far-red fluorophores such as Alexa Fluor® 647 dye or allophycocyanin (APC), facilitating multicolor analysis. This fluorophore is also expected to be useful for small animal in-vivo imaging (SAIVI) applications or for two-color western applications with the LI-COR® Odyssey® infrared imaging system. In addition to reactive dye formulations, we offer Alexa Fluor® 790 dye conjugated to a variety of antibodies, peptides, proteins, tracers, and amplification substrates optimized for cellular labeling and detection.The NHS ester (or succinimidyl ester) of Alexa Fluor® 790 is the most popular tool for conjugating this dye to a protein or antibody. NHS esters can be used to label to the primary amines (R-NH2) of proteins, amine-modified oligonucleotides, and other amine-containing molecules. The resulting Alexa Fluor® conjugate will exhibit brighter fluorescence and greater photostability than the conjugates of other spectrally similar fluorophores.

Detailed information about this AlexaFluor® NHS ester:

Fluorophore label: Alexa Fluor® 790 dye
Reactive group: NHS ester
Reactivity: Primary amines on proteins and ligands, amine-modified oligonucleotides
Ex/Em of the conjugate: 784/814 nm
Extinction coefficient: 260,000 cm-1M-1
Spectrally similar dyes: indocyanine green (ICG) and the IRDye® 800 dye
Molecular weight: ~1750

Typical Conjugation Reaction
You can conjugate amine-reactive reagents with virtually any protein or peptide (the provided protocol is optimized for IgG antibodies). You can scale the reaction for any amount of protein, but the concentration of the protein should be at least 2 mg/mL for optimal results. We recommend trying three different degrees of labeling, using three different molar ratios of the reactive reagent to protein.

The Alexa Fluor® NHS ester is typically dissolved in high-quality anhydrous dimethylformamide (DMF) or dimethylsulfoxide (DMSO) (D12345), and the reaction is carried out in 0.1–0.2 M sodium bicarbonate buffer, pH 8.3, at room temperature for 1 hour. Because the pKa of the terminal amine is lower than that of the lysine epsilon-amino group, you may achieve more selective labeling of the amine terminus using a buffer closer to neutral pH.

Conjugate Purification
Labeled antibodies are typically separated from free Alexa Fluor® dye using a gel filtration column, such as Sephadex™ G-25, BioGel® P-30, or equivalent. For much larger or smaller proteins, select a gel filtration media with an appropriate molecular weight cut-off or purify by dialysis. We offer several purification kits optimized for different quantities of antibody conjugate:
Antibody Conjugate Purification Kit for 0.5-1 mg (A33086)
Antibody Conjugate Purification Kit for 20-50 µg (A33087)
Antibody Conjugate Purification kit for 50-100 µg (A33088)

Learn More About Protein and Antibody Labeling
We offer a wide selection of Molecular Probes® antibody and protein labeling kits to fit your starting material and your experimental setup. See our Antibody Labeling kits or use our Labeling Chemistry Selection Tool for other choices. To learn more about our labeling kits, read Kits for Labeling Proteins and Nucleic Acids—Section 1.2 in The Molecular Probes® Handbook.

We’ll Make a Custom Conjugate for You
If you can’t find what you’re looking for in our online catalog, we’ll prepare a custom antibody or protein conjugate for you. Our custom conjugation service is efficient and confidential, and we stand by the quality of our work. We are ISO 9001:2000 certified.

N-(1-Pyrene)Maleimide (Invitrogen™)

The thiol-reactive N-(1-pyrene)maleimide can be used to create environment-sensitive bioconjugates with this unique fluorophore.

BODIPY™ 493/503 NHS Ester (Succinimidyl Ester) (Invitrogen™)

BODIPY® 493/503 dye is bright, green fluorescent dye with similar excitation and emission to fluorescein (FITC) or Alexa Fluor® 488 dye. It has a high extinction coefficient and fluorescence quantum yield and is relatively insensitive to solvent polarity and pH change. In contrast to the highly water soluble fluorophores Alexa Fluor® 488 dye and fluorescein (FITC), BODIPY® dyes have unique hydrophobic properties ideal for staining lipids, membranes, and other lipophilic compounds. BODIPY® 493/503 dye has a relatively long excited-state lifetime (typically 5 nanoseconds or longer), which is useful for fluorescence polarization-based assays and a large two-photon cross-section for multiphoton excitation. In addition to reactive dye formulations, we offer BODIPY® 493/503 dye conjugated to a variety of antibodies, peptides, proteins, tracers, and amplification substrates optimized for cellular labeling and detection.

The NHS ester (or succinimidyl ester) of BODIPY® 493/503 is the most popular tool for conjugating the dye to a protein or antibody. NHS esters can be used to label the primary amines (R-NH2) of proteins, amine-modified oligonucleotides, and other amine-containing molecules. The resulting BODIPY® 493/503 conjugates exhibit bright fluorescence, narrow emission bandwidths, and relatively long excited-state lifetimes, which can be useful for fluorescence polarization assays and two-photon excitation (TPE) microscopy.

This reactive dye contains a C3 alkyl spacer between the fluorophore and the NHS ester group. This spacer helps to separate the fluorophore from its point of attachment, potentially reducing the interaction of the fluorophore with the biomolecule to which it is conjugated.

Detailed information about this BODIPY® 493/503 NHS ester:

Fluorophore label: BODIPY® 493/503 dye
Reactive group: NHS ester (succinimidyl ester)
Reactivity: Primary amines on proteins and ligands, amine-modified oligonucleotides
Ex/Em of the conjugate: 500/509 nm
Extinction coefficient: 79,000 cm-1M-1
Molecular weight: 417.22

Typical Conjugation Reaction
Amine-reactive reagents can be conjugated with virtually any protein or peptide; the provided protocol is optimized for IgG antibodies. The reaction can be scaled for any amount of protein, but the concentration of the protein should be at least 2 mg/mL for optimal results. We recommend trying three different degrees of labeling, using three different molar ratios of the reactive reagent to protein.

The BODIPY® NHS ester is typically dissolved in high-quality anhydrous dimethylformamide (DMF) or dimethylsulfoxide (DMSO), and the reaction is carried out in 0.1-0.2 M sodium bicarbonate buffer, pH 8.3, at room temperature for 1 hour. Because the pKa of the terminal amine is lower than that of the lysine epsilon-amino group, you may achieve more selective labeling of the amine terminus using a buffer closer to neutral pH.

Conjugate Purification
Labeled antibodies are typically separated from free BODIPY® dye using a gel filtration column, such as Sephadex™ G-25, BioGel® P-30, or equivalent. For much larger or smaller proteins, select a gel filtration medium with an appropriate molecular weight cut-off or purify by dialysis. We offer several purification kits optimized for different quantities of antibody conjugate:
Antibody Conjugate Purification Kit for 0.5-1 mg (A33086)
Antibody Conjugate Purification Kit for 20-50 µg (A33087)
Antibody Conjugate Purification kit for 50-100 µg (A33088)

Learn More About Protein and Antibody Labeling
We offer a wide selection of Molecular Probes® antibody and protein labeling kits to fit your starting material and your experimental setup. See our Antibody Labeling kits or use our Labeling Chemistry Selection Tool for other choices. To learn more about our labeling kits, read Kits for Labeling Proteins and Nucleic Acids—Section 1.2 in The Molecular Probes® Handbook.

We’ll Make a Custom Conjugate for You
If you can’t find what you’re looking for in our online catalog, we’ll prepare a custom antibody or protein conjugate for you. Our custom conjugation service is efficient and confidential, and we stand by the quality of our work. We are ISO 9001:2000 certified.

Alexa Fluor™ 633 C5 Maleimide (Invitrogen™)

Alexa Fluor® 633 is a bright, red fluorescent dye with excitation ideally suited to the 633 nm laser line. Used for stable signal generation in imaging and flow cytometry, Alexa Fluor® 633 dye is water soluble and pH-insensitive from pH 4 to pH 10.

The maleimide derivative of Alexa Fluor® 633 is the most popular tool for conjugating the dye to a thiol group on a protein, oligonucleotide thiophosphate, or low molecular weight ligand. The resulting Alexa Fluor® 633 conjugates exhibit brighter fluorescence and greater photostability than the conjugates of other spectrally similar fluorophores.

Detailed information about this AlexaFluor® maleimide:

Fluorophore label: Alexa Fluor® 633 dye
Reactive group: maleimide
Reactivity: thiol groups on proteins and ligands, oligonucleotide thiophosphates
Ex/Em of the conjugate: 622/640 nm
Extinction coefficient: 143,000 cm-1M-1
Molecular weight: ~1300

Typical Conjugation Reaction
The protein should be dissolved at a concentration of 50-100 µM in a suitable buffer (10-100 mM phosphate, Tris, or HEPES) at pH 7.0-7.5. In this pH range, the protein thiol groups are sufficiently nucleophilic that they react almost exclusively with the reagent in the presence of the more numerous protein amine groups, which are protonated and relatively unreactive. We recommend reducing any disulfide bonds at this point using a 10-fold molar excess of reducing agent such as DTT or TCEP. Excess DTT must be removed by dialysis and subsequent thiol-modification should be carried out under oxygen-free conditions to prevent reformation of the disulfide bonds; these precautions are not necessary when using TCEP prior to maleimide conjugation.

The Alexa Fluor® maleimide is typically dissolved in high-quality anhydrous dimethylsulfoxide (DMSO) at a concentration of 1-10 mM immediately prior to use, and stock solutions should be protected from light as much as possible. Generally, this stock solution is added to the protein solution dropwise while stirring to produce approximately 10-20 moles of reagent per mole of protein, and the reaction is allowed to proceed at room temperature for 2 hours or at 4°C overnight, protected from light. Any unreacted thiol-reactive reagent can be consumed by adding excess glutathione, mercaptoethanol, or other soluble low molecular weight thiol.

Conjugate Purification
Labeled antibodies are typically separated from free Alexa Fluor® dye using a gel filtration column, such as Sephadex™ G-25, BioGel® P-30, or equivalent. For much larger or smaller proteins, select a gel filtration media with an appropriate molecular weight cut-off or purify by dialysis. We offer several purification kits optimized for different quantities of antibody conjugate:
Antibody Conjugate Purification Kit for 0.5-1 mg (A33086)
Antibody Conjugate Purification Kit for 20-50 µg (A33087)
Antibody Conjugate Purification kit for 50-100 µg (A33088)

Learn More About Protein and Antibody Labeling
We offer a wide selection of Molecular Probes® antibody and protein labeling kits to fit your starting material and your experimental setup. See our Antibody Labeling kits or use our Labeling Chemistry Selection Tool for other choices. To learn more about our labeling kits, read Kits for Labeling Proteins and Nucleic Acids—Section 1.2 in The Molecular Probes® Handbook.

We’ll Make a Custom Conjugate for You
If you can’t find what you’re looking for in our online catalog, we’ll prepare a custom antibody or protein conjugate for you. Our custom conjugation service is efficient and confidential, and we stand by the quality of our work. We are ISO 9001:2000 certified.

Alexa Fluor™ 568 Hydrazide (Invitrogen™)

Alexa Fluor® 568 Hydrazide is useful as a cell tracer and as a reactive dye for labeling aldehydes or ketones in polysaccharides or glycoproteins. Alexa Fluor® 568 is a bright, red fluorescent dye. Used for stable signal generation in imaging and flow cytometry, Alexa Fluor® 568 dye is water soluble and pH-insensitive from pH 4 to pH 10. In addition to reactive dye formulations, we offer Alexa Fluor® 568 dye conjugated to a variety of antibodies, peptides, proteins, tracers, and amplification substrates optimized for cellular labeling and detection (learn more).

Detailed information about this AlexaFluor® hydrazide:

• Fluorophore label : Alexa Fluor® 568 dye
• Reactive group: hydrazide
• Reactivity: Aldehydes or keytones in polysaccharides or glycoproteins
• Ex/Em of the conjugate: 576/599 nm
• Extinction coefficient: 86,000 cm-1M-1
• Spectrally similar dyes: Rhodamine Red
• Molecular weight: 730.74

Cell Tracking and Tracing Applications
Alexa Fluor® hydrazides and hydroxlamines are useful as low molecular weight, membrane-impermeant, aldehyde-fixable cell tracers, exhibiting brighter fluorescence and greater photostability than cell tracers derived from other spectrally similar fluorophores. They are easily loaded into cells by microinjection, infusion from patch pipette, or uptake induced by our Influx™ Pinocytic Cell-Loading Reagent. Learn more about cell tracking and tracing.

Glycoprotein and Polysaccharide Labeling Applications
The Alexa Fluor® hydrazides and hydroxlamines are reactive molecules that can be used to add a fluorescent label to biomolecules containing aldehydes or ketones. Aldehydes and ketones can be introduced into polysaccharides and glycoproteins by periodate-mediated oxidation of vicinal diols. Galactose oxidase can also be used to oxidize terminal galactose residues of glycoproteins to aldehydes.

Hydrazide vs Hydroxylamine
Hydrazine derivatives react with ketones and aldehydes to yield relatively stable hydrazones. Hydroxylamine derivatives (aminooxy compounds) react with aldehydes and ketones to yield oximes. Oximes are superior to hydrazones with respect to hydrolytic stability. Both hydrazones and oximes can be reduced with sodium borohydride (NaBH4) to further increase the stability of the linkage.

Learn More About Protein and Antibody Labeling
We offer a wide selection of Molecular Probes® antibody and protein labeling kits to fit your starting material and your experimental setup. See our Antibody Labeling kits or use our Labeling Chemistry Selection Tool for other choices. To learn more about our labeling kits, read Kits for Labeling Proteins and Nucleic Acids—Section 1.2 in The Molecular Probes® Handbook.

We’ll Make a Custom Conjugate for You
If you can’t find what you’re looking for in our online catalog, we’ll prepare a custom antibody or protein conjugate for you. Our custom conjugation service is efficient and confidential, and we stand by the quality of our work. We are ISO 9001:2000 certified.

Related Products
DMSO (dimethylsulfoxide) (D12345)
Antibody Conjugate Purification Kit for 0.5-1 mg (A33086)
Antibody Conjugate Purification Kit for 20-50 µg (A33087)
Antibody Conjugate Purification kit for 50-100 µg (A33088)

DyLight™ 488-Phosphine (Thermo Scientific™)

Thermo Scientific DyLight Fluor Phosphine Reagents are phosphine-activated fluorescent dyes for specific labeling and detection of azide-tagged molecules, which enables use of fluorescence imaging in metabolic labeling strategies.

When used in combination with azide labeling strategies, phosphine-activated DyLight Fluors enable selective fluorescent labeling for detection of protein interactions and post-translational modifications using fluorescence imaging technologies. The phosphine group conjugates to azide groups by the Staudinger reaction mechanism. Azide groups can be introduced into proteins or other cellular targets through in vivo labeling with azide-tagged derivatives of naturally occurring metabolic building blocks. Because neither phosphines nor azides are present in biological systems, they comprise a chemoselective (mutually specific) ligation pair for labeling and conjugation.

General features of the phosphine-activated DyLight Fluors:

Soluble—easily dissolves in water-miscible solvents (e.g., DMSO) for subsequent dilution in aqueous reaction mixtures with cell lysates and other biological samples
Compatible—reaction chemistry occurs effectively in simple buffer conditions; requires no accessory reagents such as copper or reducing agents, and does not interfere with fluorescence applications
Chemoselective—the phosphine reactive group is specific in biological samples for bioorthogonal azide-tagged molecules, ensuring that fluorescent labeling is specific
High-performance fluorescence—DyLight 488, 550 and 650 are intense, highly stable fluorophores for green, orange and red fluorescent detection. (see DyLight Fluors)

Related Products
DyLight™ 550-Phosphine
DyLight™ 650-Phosphine

BODIPY™ FL, STP Ester, Sodium Salt (Invitrogen™)

The amine-reactive BODIPY® FL STP ester produces electronically neutral dye conjugates that are spectrally similar to the negatively charged fluorescein dye. This dye's lack of ionic charge results in minimal effects on the isoelectric points of standard proteins conjugated with this fluorophore. The small size and relatively long excited-state lifetime of BODIPY® FL dye has proven useful for studying ligand-receptor interaction by fluoresence polarization. In addition, BODIPY® FL dye has little or no spectral overlap with longer-wavelength dyes such as tetramethylrhodamine and Texas Red® dye, making it a useful green fluorophore for multicolor applications. The STP ester has higher water solubility than simple succinimidyl esters; the resulting dye conjugate is the same.

Qdot™ 545 ITK™ Amino (PEG) Quantum Dots (Invitrogen™)

Qdot® 545 ITK™ amino (PEG) quantum dots are the ideal starting material for preparing custom conjugates of ultrabright and photostable fluorescently labeled proteins or other biopolymers. These probes are functionalized with amine-derivatized PEG, which prevents non-specific interactions and provides a convenient handle for conjugation. The amino quantum dots react efficiently with isothiocyanates and succinimidyl esters, or with native carboxylic acids using water-soluble carbodiimides such as EDC. Such derivatives may be used for various labeling and tracking applications that require ultrabright and stable fluorescence. Our Qdot® ITK™ amino quantum dots are provided as 8 µM solutions and are available in 8 colors of Qdot® probes.

Important Features of Qdot® ITK™ Amino Quantum Dots:
• Qdot® 545 ITK™ amino quantum dot has emission maxima of ~545 nm
• Extremely photostable and bright fluorescence
• Efficiently excited with single-line excitation sources
• Narrow emission, large stokes shift
• Available in multiple colors
• Ideal for various labeling and tracking applications


Properties of Qdot® Nanocrystals
Qdot® probes are ideal for imaging and labeling applications that require bright fluorescent signals and/or real-time tracking. Unique among fluorescent reagents, all nine available colors of Qdot® probes can be simultaneously excited with a single (UV to blue-green) light source. This property makes these reagents excellent for economical and user-friendly multiplexing applications. Qdot® labels are based on semiconductor nanotechnology and are similar in scale to moderately sized proteins.

About the Innovator’s Tool Kit Qdot® ITK™ Reagents
These Qdot® ITK™ probes are ideal for researchers who wish to prepare specific (non-stocked) conjugates for their applications and need customizable conjugation functionality.

Other Forms of Qdot® Nanocrystals are Available
In addition to the amine-derivatized form, we offer Qdot® ITK™ quantum dots with carboxyl and aliphatic hydrocarbon modifications. We’ve also developed a wide range of Qdot® nanocrystals conjugates and labeling kits. Investigate the properties of Qdot® nanocrystals or read the Molecular Probes® Handbook Section 6.6—Qdot® Nanocrystals to find out more.

For Research Use Only. Not intended for any animal or human therapeutic or diagnostic use.

BODIPY™ FL-X NHS Ester (Succinimidyl Ester) (Invitrogen™)

BODIPY® FL-X dye is bright, green fluorescent dye with similar excitation and emission to fluorescein (FITC) or Alexa Fluor® 488 dye. It has a high extinction coefficient and fluorescence quantum yield and is relatively insensitive to solvent polarity and pH change. In contrast to the highly water soluble fluorophores Alexa Fluor® 488 dye and fluorescein (FITC), BODIPY® dyes have unique hydrophobic properties ideal for staining lipids, membranes, and other lipophilic compounds. BODIPY® FL-X dye has a relatively long excited-state lifetime (typically 5 nanoseconds or longer), which is useful for fluorescence polarization-based assays and a large two-photon cross-section for multiphoton excitation. In addition to reactive dye formulations, we offer BODIPY® FL-X dye conjugated to a variety of antibodies, peptides, proteins, tracers, and amplification substrates optimized for cellular labeling and detection (learn more).

The NHS ester (or succinimidyl ester) of BODIPY® FL-X is the most popular tool for conjugating the dye to a protein or antibody. NHS esters can be used to label the primary amines (R-NH2) of proteins, amine-modified oligonucleotides, and other amine-containing molecules. The resulting BODIPY® FL-X conjugates exhibit bright fluorescence, narrow emission bandwidths, and relatively long excited-state lifetimes, which can be useful for fluorescence polarization assays and two-photon excitation (TPE) microscopy.

This reactive dye contains a seven-atom aminohexanoyl ("X") spacer between the fluorophore and the NHS ester group. This spacer helps to separate the fluorophore from its point of attachment, potentially reducing the interaction of the fluorophore with the biomolecule to which it is conjugated.

Detailed information about this BODIPY® FL-X NHS ester:

Fluorophore label: BODIPY® FL-X dye
Reactive group: NHS ester (succinimidyl ester)
Reactivity: Primary amines on proteins and ligands, amine-modified oligonucleotides
Ex/Em of the conjugate: 504/510 nm
Extinction coefficient: 85,000 cm-1M-1
Molecular weight: 502.32

Typical Conjugation Reaction
Amine-reactive reagents can be conjugated with virtually any protein or peptide; the provided protocol is optimized for IgG antibodies. The reaction can be scaled for any amount of protein, but the concentration of the protein should be at least 2 mg/mL for optimal results. We recommend trying three different degrees of labeling, using three different molar ratios of the reactive reagent to protein.

The BODIPY® NHS ester is typically dissolved in high-quality anhydrous dimethylformamide (DMF) or dimethylsulfoxide (DMSO), and the reaction is carried out in 0.1-0.2 M sodium bicarbonate buffer, pH 8.3, at room temperature for 1 hour. Because the pKa of the terminal amine is lower than that of the lysine epsilon-amino group, you may achieve more selective labeling of the amine terminus using a buffer closer to neutral pH.

Conjugate Purification
Labeled antibodies are typically separated from free BODIPY® dye using a gel filtration column, such as Sephadex™ G-25, BioGel® P-30, or equivalent. For much larger or smaller proteins, select a gel filtration medium with an appropriate molecular weight cut-off or purify by dialysis. We offer several purification kits optimized for different quantities of antibody conjugate:
Antibody Conjugate Purification Kit for 0.5-1 mg (A33086)
Antibody Conjugate Purification Kit for 20-50 µg (A33087)
Antibody Conjugate Purification kit for 50-100 µg (A33088)

Learn More About Protein and Antibody Labeling
We offer a wide selection of Molecular Probes® antibody and protein labeling kits to fit your starting material and your experimental setup. See our Antibody Labeling kits or use our Labeling Chemistry Selection Tool for other choices. To learn more about our labeling kits, read Kits for Labeling Proteins and Nucleic Acids—Section 1.2 in The Molecular Probes® Handbook.

We’ll Make a Custom Conjugate for You
If you can’t find what you’re looking for in our online catalog, we’ll prepare a custom antibody or protein conjugate for you. Our custom conjugation service is efficient and confidential, and we stand by the quality of our work. We are ISO 9001:2000 certified.

Zenon™ Alexa Fluor™ 555 Rabbit IgG Labeling Kit (Invitrogen™)

Zenon® labeling technology provides a fast, versatile, and reliable method for adding a fluorescent label to an antibody. You need only a small amount of starting material, and the method is optimized for efficient labeling of antibodies in serum, ascites fluid, or hybridoma suspensions. Antibody conjugates formed using Zenon® technology may be used in any protocol where a directly labeled primary antibody is suitable, including flow cytometry, imaging, and high-throughput applications. This exclusive Molecular Probes® Zenon® labeling technology greatly simplifies the use of multiple mouse-derived antibodies in the same staining protocol.

Important Features of Zenon® Labeling Technology:

• Labeled antibodies typically ready to use in 10 minutes
• Requires only 1–20 μg primary antibody
• Simple, no purification required
• Flexible–over 24 fluorophores plus biotin, HRP, alkaline phosphatase, and TSA to choose from
• Multiplex with other mouse monoclonal antibodies simultaneously


Save Time and Antibody
Each kit comes with affinity-purified monovalent Fab fragment of a goat anti-Fc antibody (or, in the case of the Zenon® Goat IgG Labeling Kits, a rabbit anti-Fc antibody) that has been conjugated to one of our premier Alexa Fluor® dyes or to Pacific Blue™, Pacific Orange™, fluorescein, or Texas Red®-X dyes, biotin R-phycoerythrin (R-PE), allophycocyanin (APC), HRP, or alkaline phosphatase.

Formation of the Fab–antibody complex with the Zenon® Antibody Labeling Kits is extremely fast (5 min for complex, 5 min for blocking step). And Zenon® labeling is a reliable and reproducible method, even with as low 0.4 μg in 2 μL of primary antibody. There is minimal waste of expensive or difficult-to-obtain antibodies when using the Zenon® Antibody Labeling Kits.

Preserve Primary Antibody Function and Affinities
Reactive dye labeling of primary antibodies can have unpredictable and undesirable outcomes. Among these are reduced binding affinities by label addition in the binding pocket. Zenon® antibody labeling approach, targeted to the Fc tail, avoids this concern.

Moreover the Zenon® dye- and enzyme-labeled Fab fragments have been affinity purified during their preparation to help ensure their high affinity and selectivity for the Fc portion of the corresponding primary antibody. The procedure for chemical labeling of the Fab fragments protects the Fc-binding site, resulting in more active labeling reagents.

Many Fluorophore and Enzyme Labels Available
Zenon® immunolabeling technology makes it very easy to change fluorescent color combinations or detection methodologies by simply using a different dye- or enzyme-labeled Fab fragment from our extensive selection of over 100 Zenon® Antibody Labeling Kits. If larger quantities or covalent attachment of the label is desired, see Antibody Labeling from A to Z or use our Labeling Chemistry Selection Tool for other choices.

Zenon® Technology Simplifies the Use of Multiple Antibodies of the Same Isotype in the Same Protocol
The stability of the Zenon® complex is sufficient to allow sequential (or simultaneous) labeling of different targets in cells and tissues with multiple antibody complexes. Subsequent to staining, an aldehyde-based fixation step can permanently block the transfer of Zenon® labels between different primary antibodies and will preserve the staining pattern.

We’ll Make a Custom Antibody Conjugate for You
If you can’t find what you’re looking for in our stocked list, we’ll prepare a custom antibody conjugate for you. Our custom conjugation service is efficient and confidential, and we stand by the quality of our work. We are ISO 9001:2000 certified.

For Research Use Only. Not intended for animal or human therapeutic or diagnostic use.

Related Links:

Zenon® Labeling Technology
Zenon® Technology: Versatile Reagents for Immunolabeling—Section 7.3

Molecular Probes® Cell Imaging Kit (Invitrogen™)

Fluorescence imaging protocols are sometimes complicated and tedious, with more time spent preparing samples and reagents than acquiring images and data. To help researchers focus more on biology and get results faster, we have developed a set of imaging reagents that emphasize user friendliness and workflow convenience.

The Molecular Probes® Cell Imaging Kit contains the following products:

NucBlue™ Live ReadyProbes™ Reagent (Cat. No. R37605)
NucRed™ Live 647 ReadyProbes™ Reagent (Cat. No. R37106)
ReadyProbes™ Cell Viability Imaging Kit, Blue/Green (Cat. No. R37609)
Goat Anti-Rabbit IgG (H+L) Secondary Antibody, Alexa Fluor™ 594 conjugate (Cat. No. R37117)
Goat Anti-Mouse lgG Secondary Antibody, Alexa Fluor™ 488 conjugate (Cat. No. R37120)
Image-iT™ FX Signal Enhancer ReadyProbes™ Reagent (Cat. No. R37107)

Zenon™ Alexa Fluor™ 647 Mouse IgG1 Labeling Kit (Invitrogen™)

Zenon® labeling technology provides a fast, versatile, and reliable method for adding a fluorescent label to an antibody. You need only a small amount of starting material, and the method is optimized for efficient labeling of antibodies in serum, ascites fluid, or hybridoma suspensions. Antibody conjugates formed using Zenon® technology may be used in any protocol where a directly labeled primary antibody is suitable, including flow cytometry, imaging, and high-throughput applications. This exclusive Molecular Probes® Zenon® labeling technology greatly simplifies the use of multiple mouse-derived antibodies in the same staining protocol.

Important Features of Zenon® Labeling Technology:

• Labeled antibodies typically ready to use in 10 minutes
• Requires only 1–20 μg primary antibody
• Simple, no purification required
• Flexible–over 24 fluorophores plus biotin, HRP, alkaline phosphatase, and TSA to choose from
• Multiplex with other mouse monoclonal antibodies simultaneously


Save Time and Antibody
Each kit comes with affinity-purified monovalent Fab fragment of a goat anti-Fc antibody (or, in the case of the Zenon® Goat IgG Labeling Kits, a rabbit anti-Fc antibody) that has been conjugated to one of our premier Alexa Fluor® dyes or to Pacific Blue™, Pacific Orange™, fluorescein, or Texas Red®-X dyes, biotin R-phycoerythrin (R-PE), allophycocyanin (APC), HRP, or alkaline phosphatase.

Formation of the Fab–antibody complex with the Zenon® Antibody Labeling Kits is extremely fast (5 min for complex, 5 min for blocking step). And Zenon® labeling is a reliable and reproducible method, even with as low 0.4 μg in 2 μL of primary antibody. There is minimal waste of expensive or difficult-to-obtain antibodies when using the Zenon® Antibody Labeling Kits.

Preserve Primary Antibody Function and Affinities
Reactive dye labeling of primary antibodies can have unpredictable and undesirable outcomes. Among these are reduced binding affinities by label addition in the binding pocket. Zenon® antibody labeling approach, targeted to the Fc tail, avoids this concern.

Moreover the Zenon® dye- and enzyme-labeled Fab fragments have been affinity purified during their preparation to help ensure their high affinity and selectivity for the Fc portion of the corresponding primary antibody. The procedure for chemical labeling of the Fab fragments protects the Fc-binding site, resulting in more active labeling reagents.

Many Fluorophore and Enzyme Labels Available
Zenon® immunolabeling technology makes it very easy to change fluorescent color combinations or detection methodologies by simply using a different dye- or enzyme-labeled Fab fragment from our extensive selection of over 100 Zenon® Antibody Labeling Kits. If larger quantities or covalent attachment of the label is desired, see Antibody Labeling from A to Z or use our Labeling Chemistry Selection Tool for other choices.

Zenon® Technology Simplifies the Use of Multiple Antibodies of the Same Isotype in the Same Protocol
The stability of the Zenon® complex is sufficient to allow sequential (or simultaneous) labeling of different targets in cells and tissues with multiple antibody complexes. Subsequent to staining, an aldehyde-based fixation step can permanently block the transfer of Zenon® labels between different primary antibodies and will preserve the staining pattern.

We’ll Make a Custom Antibody Conjugate for You
If you can’t find what you’re looking for in our stocked list, we’ll prepare a custom antibody conjugate for you. Our custom conjugation service is efficient and confidential, and we stand by the quality of our work. We are ISO 9001:2000 certified.

For Research Use Only. Not intended for animal or human therapeutic or diagnostic use.

Related Links:

Zenon® Labeling Technology
Zenon® Technology: Versatile Reagents for Immunolabeling—Section 7.3

Alexa Fluor™ 532 Antibody Labeling Kit (Invitrogen™)

Molecular Probes® Alexa Fluor® Antibody Labeling Kits provide a convenient means to label small amounts of antibodies with Alexa Fluor® dyes (choice of 10 colors). This kit is optimized for labeling 100 µg of antibody per reaction with green-yellow fluorescent Alexa Fluor® 532. Comparably small amounts of other proteins (>40 kDa) can also be labeled.

The kit contains everything you need to perform five separate labeling reactions as well as to purify the resulting conjugates. Conjugates are ideal for multiple applications, including flow cytometry, fluorescent microscopy, immunohistochemistry, primary detection, ELISAs, immunocytochemistry, indirect FISH, and more.

Important Features of Alexa Fluor® 532 Antibody Labeling Kit:
• With an excitation and emission maximum of 530/554 nm, Alexa Fluor® 532 can be efficiently excited using a 532 nm Nd:YAG laser line and detected under standard Rhodamine 6G filters
• Labeled proteins typically ready to use typically in 90 min (~15 min hands-on time)
• Useful for labeling 100 µg of protein
• Optimized for small-scale labeling of any protein >40 kDa
• Purified using convenient spin filters
• Stabilizing proteins must be removed from the sample before labeling
• Includes detailed instructions for determining degree of labeling (DOL)


Better Results and Workflows with Primary labeled antibodies
A primary antibody directly labeled with a fluorophore often produces lower background fluorescence and less nonspecific binding. Further, multiple primary antibodies of the same isotype or derived from the same species can easily be used in the same experiment if they are directly labeled with compatible fluorophores.

Superior Alexa Fluor® Dyes
Compared to traditional dyes, Alexa Fluor® dyes are brighter, more photostable, and more pH resistant between pH 4 and 10. And generally when using Alexa Fluor® dyes, higher degrees of labeling can be achieved without intramolecular quenching. For details see Alexa Fluor® Dyes Spanning the Visible and Infrared Spectrum—Section 1.3.

Learn More About Protein and Antibody Labeling
We offer a wide selection of Molecular Probes® antibody and protein labeling kits to fit your starting material and your experimental setup. See Antibody Labeling from A to Z or use our Labeling Chemistry Selection Tool for other choices. To learn more about our various kits read Kits for Labeling Proteins and Nucleic Acids—Section 1.2 in the Molecular Probes® Handbook.

We'll Make a Custom Antibody Conjugate for You
If you can't find what you're looking for in our stocked list, we'll prepare a custom antibody conjugate for you. Our custom conjugation service is efficient and confidential, and we stand by the quality of our work. We are ISO 9001:2000 certified.

For Research Use Only. Not for use in diagnostic procedures.

EZ-Link™ Micro Sulfo-NHS-LC-Biotinylation Kit (Thermo Scientific™)

The Thermo Scientific EZ-Link Sulfo-NHS-LC-Biotinylation Kit contains reagents sufficient for 8 biotinylation reactions (e.g., 0.05–0.2 mg antibody per reaction). The EZ-Link Sulfo-NHS-LC-Biotin reagent included in the kit is an intermediate-length, water-soluble biotinylation reagent for labeling antibodies, proteins, and other molecules that have primary amines.

Features of EZ-Link Sulfo-NHS-LC-Biotin:

Protein labeling—biotinylate antibodies to facilitate immobilization, purification or detection using streptavidin resins or probes
Cell surface labeling—biotinylates only surface proteins of whole cells because the negatively charged reagent does not permeate cell membranes
Amine-reactive—reacts with primary amines (-NH2), such as lysine side-chains, or the amino-termini of polypeptides
Soluble—charged sulfo-NHS group increases reagent water solubility compared to ordinary NHS-ester compounds
Irreversible—forms permanent amide bonds; spacer arm cannot be cleaved
Medium length—spacer arm (total length added to target) is 22.4 angstroms; provides excellent balance between adequate length (minimal steric hindrance for biotin binding) and modest mass

Sulfo-NHS-LC-Biotin is one of three very similar EZ-Link Reagents that are water-soluble, non-cleavable, and enable simple and efficient biotinylation of antibodies, proteins and any other primary amine-containing macromolecules in solution. Specific labeling of cell surface proteins is another common application for these uniquely water-soluble and membrane impermeable reagents. Differing only in their spacer arm lengths, the three Sulfo-NHS-ester reagents offer the possibility of optimizing labeling and detection experiments where steric hindrance of biotin binding is an important factor. Sulfo-NHS-LC-Biotin is offered in several package sizes and as complete protein labeling kits.

We manufacture biotin reagents to ensure the highest possible overall product integrity, consistency, and performance for the intended research applications.

N-Hydroxysulfosuccinimide (NHS) esters of biotin are the most popular type of biotinylation reagent. NHS-activated biotins react efficiently with primary amino groups (-NH2) in alkaline buffers to form stable amide bonds. Proteins (e.g., antibodies) typically have several primary amines that are available as targets for labeling, including the side chain of lysine (K) residues and the N-terminus of each polypeptide.

Varieties of biotin NHS-ester reagents differ in length, solubility, cell permeability and cleavability. Non-sulfonated NHS-biotins are cell permeable but must be dissolved in organic solvent such as DMSO or DMF. Sulfo-NHS biotins (and those with pegylated spacers) are directly water soluble but not membrane permeable. Varieties containing disulfide bonds can be cleaved using reducing agents, enabling the biotin group to be disconnected from the labeled protein.

Related Products
EZ-Link™ Sulfo-NHS-LC-Biotin
EZ-Link™ Sulfo-NHS-LC-Biotinylation Kit

GlycanAssure™ APTS Kit (Applied Biosystems™)

The GlycanAssure™ APTS Kit is part of the GlycanAssure™ Glycan Analysis and Quantitation System and contains all reagents and buffers needed to analyze and quantitate N-glycans from glycoprotein samples. The GlycanAssure APTS N-glycan sample prep method consists of rapid deglycosylation using PNGase-F enzyme followed by magnetic bead-based glycan purification, glycan labeling with ATPS dye, and excess dye removal. APTS is a traditional dye used for glycan labeling for the past several years, and the labeled glycans can be analyzed using capillary electrophoresis (CE) or liquid chromatography (LC) system. The GlycanAssure sample prep workflow does not include time-consuming vacuum centrifugation steps or the use of toxic sodium cyanoborohydride like more traditional workflows, resulting in a streamlined, automatable method for the processing and analysis of 96 samples in ~9 hrs (< 4 hrs hands-on time).

The GlycanAssure APTS kit contains:
• GlycanAssure core reagents
• GlycanAssure beads
• GlycanAssure APTS labeling reagents
• GlycanAssure kits user guide

GlycanAssure Glycan Analysis and Quantitation System
The GlycanAssure Glycan Analysis and Quantitation System is the first glycan analysis system that provides both high throughput and high data quality through an integrated glycan analysis platform that helps save labor, time, and cost of analysis. The GlycanAssure system offers simple and easy magnetic bead-based sample preparation with multiple fluorescent dyes for glycan labeling, multi-capillary Sanger sequencing instruments for high-throughput CE-LIF-based glycan analysis, and assay-specific software for fast data analysis and reporting.

As part of the GlycanAssure Glycan Analysis and Quantitation System, the 3500 Genetic Analyzer for Protein Quality Analysis and 3500xL Genetic Analyzer for Protein Quality Analysis are multi-capillary CE instruments that enable parallel analysis of 8 or 24 samples on a 50-cm capillary array for high-throughput and high-resolution glycan analysis. The ability to analyze samples in parallel avoids the need for shortened run times to achieve high throughput. The 3500 Series systems for protein quality analysis come with integrated assay-specific GlycanAssure data acquisition and data analysis software for optimum performance and user experience.

CellVue™ Maroon Cell Labeling Kit (Invitrogen™)

CellVue™ dyes are lipophilic dyes that can be used to label the cell membrane for the purpose of identifying and tracking labeled cells. Cell labeling is rapid and stable and can be combined with fluorescently labeled antibodies and other markers of cellular function for flow cytometric analysis and fluorescent microscopy. The Mini CellVue™ Kits are supplied with one vial of dye stock (1 mM in ethanol) and one vial of labeling vehicle (Diluent C).

CellVue™ Maroon is a far-red fluorescent cell labeling reagent. It is optimally excited at 647 nm and has a peak emission of 667 nm; however, it can be detected equally in filter sets designed for APC, Alexa Fluor™ 700, and APC-eFluor™ 780 or similar fluorochromes. Therefore, using antibodies conjugated to these fluorochromes in combination with using CellVue™ Maroon is not recommended.

Reported Application
Microscopy, Cell Labeling, Immunocytochemistry, Flow Cytometric Analysis

Zenon™ Pacific Blue™ Mouse IgG1 Labeling Kit (Invitrogen™)

Zenon™ labeling technology provides a fast, versatile, and reliable method for adding a fluorescent label to an antibody. You need only a small amount of starting material, and the method is optimized for efficient labeling of antibodies in serum, ascites fluid, or hybridoma suspensions. Antibody conjugates formed using Zenon™ technology may be used in any protocol where a directly labeled primary antibody is suitable, including flow cytometry, imaging, and high-throughput applications. This exclusive Molecular Probes™ Zenon™ labeling technology greatly simplifies the use of multiple mouse-derived antibodies in the same staining protocol.

View a selection guide for all Zenon™ antibody labeling kits and other antibody labeling products.

Important features of Zenon™ labeling technology:

• Labeled antibodies typically ready to use in 10 minutes
• Requires only 1–20 µg primary antibody
• Simple, no purification required
• Flexible–over 24 fluorophores plus biotin, HRP, alkaline phosphatase, and TSA to choose from
• Multiplex with other mouse monoclonal antibodies simultaneously


Save time and antibody
Each kit comes with affinity-purified monovalent Fab fragment of a goat anti-Fc antibody (or, in the case of the Zenon™ Goat IgG Labeling Kits, a rabbit anti-Fc antibody) that has been conjugated to one of our premier Alexa Fluor™ dyes or to Pacific Blue™, Pacific Orange™, fluorescein, or Texas Red™-X dyes, biotin R-phycoerythrin (R-PE), allophycocyanin (APC), HRP, or alkaline phosphatase.

Formation of the Fab–antibody complex with the Zenon™ Antibody Labeling Kits is extremely fast (5 min for complex, 5 min for blocking step). And Zenon™ labeling is a reliable and reproducible method, even with as low 0.4 µg in 2 µL of primary antibody. There is minimal waste of expensive or difficult-to-obtain antibodies when using the Zenon™ Antibody Labeling Kits.

Preserve primary antibody function and affinities
Reactive dye labeling of primary antibodies can have unpredictable and undesirable outcomes. Among these are reduced binding affinities by label addition in the binding pocket. Zenon™ antibody labeling approach, targeted to the Fc tail, avoids this concern.

Moreover the Zenon™ dye- and enzyme-labeled Fab fragments have been affinity purified during their preparation to help ensure their high affinity and selectivity for the Fc portion of the corresponding primary antibody. The procedure for chemical labeling of the Fab fragments protects the Fc-binding site, resulting in more active labeling reagents.

Many fluorophore and enzyme labels available
Zenon™ immunolabeling technology makes it very easy to change fluorescent color combinations or detection methodologies by simply using a different dye- or enzyme-labeled Fab fragment from our extensive selection of over 100 Zenon™ Antibody Labeling Kits. If larger quantities or covalent attachment of the label is desired, see Antibody Labeling from A to Z or use our Labeling Chemistry Selection Tool for other choices.

Zenon™ technology simplifies the use of multiple antibodies of the same isotype in the same protocol
The stability of the Zenon™ complex is sufficient to allow sequential (or simultaneous) labeling of different targets in cells and tissues with multiple antibody complexes. Subsequent to staining, an aldehyde-based fixation step can permanently block the transfer of Zenon™ labels between different primary antibodies and will preserve the staining pattern.

We’ll make a custom antibody conjugate for you
If you can’t find what you’re looking for in our stocked list, we’ll prepare a custom antibody conjugate for you. Our custom conjugation service is efficient and confidential, and we stand by the quality of our work. We are ISO 9001:2000 certified.

Related Links:
Zenon™ Labeling Technology
Zenon™ Technology: Versatile Reagents for Immunolabeling—Section 7.3

DyLight™ 780-B3 NHS Ester (Thermo Scientific™)

Thermo Scientific DyLight near-infrared specialty dyes, comparable to Alexa Fluor and IRDye NIR dyes, can be used to label antibodies, peptides, and other proteins at primary amines. DyLight 780-B3 dye has a structure based on the benzopyrillium core, with 3 sulfonates. It has excitation and emission peaks at 785 and 794 nm, respectively (in ethanol).

General characteristics of DyLight near-infrared emitting specialty dyes:

Large selection—the largest family of dyes available for NIR fluorescence applications
NHS ester reactive group—allows immediate labeling of antibodies, proteins, peptides and other amine-containing molecules through amide bond formation
Broad spectrum of water solubilities—choose from hydrophilic to hydrophobic dyes to optimize the right dye label for the best performance in a given application
NIR dyes avoid background interference—DyLight NIR Dyes avoid fluorescence interference or quenching effects from biomolecules present in samples
Excellent signal penetration through cells and tissues—DyLight NIR Dyes provide the optimal window for excitation and emission for in vivo imaging applications

DyLight NIR Dyes are a family of labeling agents that can be used for bright fluorescence detection in cell-based imaging or in vivo imaging applications. NIR dyes can be selected based upon their characteristic excitation and emission properties or relative hydrophilicity and hydrophobicity attributes. Dyes that contain a greater number of negatively charged sulfonates generally will have greater water solubility than dyes with fewer sulfonates. More hydrophobic dyes often provide better cell penetrating ability in vivo, while more hydrophilic dyes have less nonspecific binding potential. Each dye contains an amine-reactive NHS ester for simple modification of antibodies, proteins, peptides or other biomolecules through amide bond formation. NIR dyes are best for imaging through tissues and away from indigenous fluorescent biomolecule interference or quenching. DyLight Near Infrared Dyes represent the largest selection of fluorescent labels that are commercially available.

Criteria to consider when choosing a DyLight NIR Specialty Dye
• Excitation and emission wavelengths—choose the best dye to match the excitation and emission capabilities of your instrument
• Water solubility—choose a DyLight NIR Dye based on its relative hydrophilicity, which directly correlates to the number of negatively-charged sulfonates it has on its core structure. More hydrophilic dyes are best at maintaining water solubility of a labeled antibody and limiting the nonspecific binding of the conjugate. More hydrophobic dyes often are best at penetrating tissues and cell membranes in vivo, meaning that dyes with fewer sulfonates may work best for some applications.
• DyLight Dye selection—the broad selection of NIR dyes allows a number of candidate dyes to be tested in a given application for optimal performance.

Applications:
In vivo or ex vivo imaging
• Tumor imaging with labeled peptides
• NIR fluorescence (NIRF) imaging of labeled silica nanoparticles
• NIR in vitro imaging and characterization
• Determination of thermal stability
• Cytotoxicity assays
• Molecular imaging
• UV-VIS-NIR spectroscopy
• Fluorescence correlation spectroscopy
• MRI applications
• DNA sequencing
• Primer labeling for PCR
• 2-D gel electrophoresis
• Flow cytometry/fluorescence-activated cell sorting (FACS)
• Laser scanning confocal microscopy

Related Products
DyLight™ 780-B1 NHS Ester
DyLight™ 780-B2 NHS Ester
DyLight™ 830-B2 NHS Ester