Shop All Protein Labeling Kits

Pacific Orange™ Protein Labeling Kit (Invitrogen™)

From start to finish, it takes less than three hours to label a protein and purify the resulting conjugate using the Pacific Orange™ Protein Labeling Kit. Although optimized for 1 mg of an IgG antibody, this kit can be used to make conjugates of other proteins larger than ~40,000 daltons. The kit provides sufficient material to perform three protein conjugations and purifications. To label 100 µg of an IgG, we have the Pacific Orange™ Monoclonal Antibody Labeling Kit P30014.

View a selection guide for all Protein Labeling Kits.

View the Fluorophore Selection Guide.

pHrodo™ Red Microscale Labeling Kit (Invitrogen™)

pHrodo® Red is the new name for pHrodo®, a fluorogenic dye that dramatically increases in fluorescence as the pH of its surroundings become more acidic. Original pHrodo® and pHrodo® Red dyes are the same molecule. Use this pHrodo® Red microscale protein labeling kits to conveniently label 3 separate samples of small amounts (20-100 µg) of purified protein or antibody with pHrodo®-SE conjugate.

pHrodo® Red dye conjugates are non-fluorescent outside the cell, but fluoresce bright red in phagosomes, making them ideal tools for studies ranging from phagocytosis of bioparticles to receptor internalization. pHrodo Red™ offers staining that is faster and more accurate than ratiometric dyes.

The pHrodo® Red Microscale Labeling Kit Is:
Convenient—Labeling typically takes 2 hours with less than 30 min hands-on
Versatile—Label proteins with MW between 12 and 150 kDa
Customizable—Create your own probes for studying phagocytosis and endocytosis

Get Better Results in Endocytosis Studies
Endocytosis and phagocytosis underly physiological events ranging from host-pathogen response to receptor desensitization via internalization (as is common in the GPCR class of receptors). Once internalized, material can be acidified in endosomes or lysosomes. When conjugated to target molecules, our pHrodo® Red dye fluorogenic pH sensitive probe allows direct visual monitoring of material entering these acidic compartments. At neutral and basic pH values, pHrodo® Red dye emission is at its minimum; with acidification, pHrodo® Red dye emission is increased by as much as 8-fold (at pH 4). The fluorescence of pHrodo® Red dye is dimmed by complete media and whole blood, further improving the signal-to-noise ratio. The pHrodo® Red Microscale Labeling Kit can label proteins with molecular weights between 12 and 150 kDa, including IgG antibodies (~150 kDa) in quantities ranging from 20-100 µg.

Gain Experimental Flexibility with a Validated Technology
pHrodo® has been cited in over 150 publications and used in a variety of applications. It is validated in flow cytometry, high throughput and high content screening (HTS and HCS), and other imaging applications. pHrodo® Red offers reduced signal variability and improved timing compared to ratiometric dyes like BCECF and SNARF, and the lack of fluorescence outside the cell eliminates the need for wash steps and quencher dyes. The red fluorescence of pHrodo® Red is ideal for multiplexing applications with green-fluorescent compounds such GFP, Fluo-4, or calcein.

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

Alexa Fluor™ 647 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.

Click-IT™ Geranylgeranyl Alcohol, Azide, mixed isomers (Invitrogen™)

Identify and characterize geranylated proteins with Click-iT® geranylgeranyl alcohol, azide using the powerful click chemistry, a simple and robust two-step labeling and detection technique. In step one, the azide-containing biomolecule is fed to cells or animals and actively incorporated into proteins. Unlike other labels such as biotin or a fluorescent dye, the azide-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 and azide and an alkyne where the modified protein is detected with the corresponding alkyne-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.

Alexa Fluor™ 594 Microscale Protein Labeling Kit (Invitrogen™)

Microscale Protein Labeling Kits provide a convenient means for attaching a fluorescent label to a small amount of antibody or protein (20–100 µg). The kits are available in four Alexa Fluor® colors (or biotin) and supply everything needed for three labeling and separation reactions.

Important Features of Microscale Protein Labeling Kits:
• Labeled proteins typically ready to use typically in 2 hours (~30 minutes hands-on time)
• Optimized for 20–100 µg of protein with molecular weights between 12 and 150 kDa
• Purified using convenient spin filters with yields between 60 and 90%
• Stabilizing proteins must be removed from the sample before labeling

Stable Reaction Chemistry and Superior Alexa Fluor® Dyes
In the Microscale Protein Labeling Kits, the reactive dye contains a succinimidyl (NHS) ester moiety that reacts with primary amines of proteins to form stable dye-protein conjugates. 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.

Click-iT™ HPG Alexa Fluor™ 488 Protein Synthesis Assay Kit (Invitrogen™)

The Click-iT® HPG Alexa Fluor® 488 Protein Synthesis Assay Kit provides a fast, sensitive, non-toxic, and non-radioactive method for the detection of nascent protein synthesis utilizing fluorescence microscopy, high-content imaging, or flow cytometry. Included in the kit are L-homopropargylglycine (HPG), an amino acid analog of methionine containing an alkyne moiety, and Alexa Fluor® 488 azide. The HPG is fed to cultured cells and incorporated into proteins during active protein synthesis. Addition of the Alexa Fluor® 488 azide leads to a chemoselective ligation or "click" reaction between the green fluorescent azide and the alkyne, allowing the modified proteins to be detected by imaged-based analysis.

Non-radioactive alternative—an alternative to the traditional 35S-methionine
Visualize bulk protein dynamics—fluorescent tagging of proteins allows their localization to be determined, including aggregation
Specificity—selective, specific reaction between label and detection tags
Stability —product contains an irreversible, covalent bond
Multiplex-enabled—use in conjuction with Click®-iT AHA (azide amino acid and alkyne dye) to detect spatial and temporal differences
Applicability to biological samples—easy detection; high sensitivity and low background, regardless of complexity

The Click-iT® HPG Alexa Fluor® 488 Protein Synthesis Assay Kit has been successfully tested in HeLa, A549, and U-2 OS cells with a variety of reagents that inhibit protein synthesis, including cycloheximide and anisomycin. The applicability of these probes to monitor protein degradation has also been shown using inhibitors of the proteasome (MG132 and Bortezomib) and blockers of autophagy (chloroquine) in HeLa cells.

Additionally, due to differences in Click-iT® chemistry between the Click-iT® HPG Alexa Fluor® 488 Protein Synthesis Assay Kit and Click®-iT AHA with Alexa Fluor® 594 Alkyne, these reagents can be used in conjunction for spatial or temporal determination of differences in nascent protein synthesis.

Pierce™ Biotin Quantitation Kit (Thermo Scientific™)

Thermo Scientific Pierce Biotin Quantitation Kit includes aliquots of HABA reagent and biotinylated protein standard for convenient colorimetric determination of biotinylation levels in labeled antibodies and other proteins.

Features of the Biotin Quantitation Kit:

Colorimetric – requires a plate reader or spectrophotometer set to measure at 500nm
Reliable – proven, well-characterized method for determination of biotinylation levels
Convenient – kit provides the essential reagents and standards to perform the assay with ease
Flexible – adaptable to spectrophotometer cuvettes or standard plate readers with 96-well microplates
Options – calculate results directly from absorbance values based on extinction coefficients using the procedure outlined in the instructions
Robust – supplied HABA-avidin complex can be used over a wide range of pH and salt concentrations

HABA dye (4'-hydroxyazobenzene-2-carboxylic acid) is a reagent that enables quick estimation of the mole-to-mole ratio of biotin to protein in a solution. The Pierce Biotin Quantitation Kit contains a premix of HABA and avidin and a biotinylated horseradish peroxidase (HRP) positive control. The HABA-Avidin Premix is supplied in convenient Thermo Scientific No-Weigh Microtube packaging, which eliminates the difficulties associated with weighing small quantities of reagent.

To quantitate biotinylation, a solution containing the biotinylated protein is added to a mixture of HABA and avidin. Because of its higher affinity for avidin, biotin displaces the HABA and the absorbance at 500nm decreases proportionately. By this method, an unknown amount of biotin present in a solution can be quantitated in a single cuvette by measuring the absorbance of the HABA-avidin solution before and after addition of the biotin-containing sample. The change in absorbance relates to the amount of biotin in the sample by the extinction coefficient of the HABA-avidin complex. View online HABA Calculator.

Biotin-XX Microscale Protein Labeling Kit (Invitrogen™)

Microscale Protein Labeling Kits provide a convenient means for attaching a fluorescent label to a small amount of antibody or protein (20–100 µg). The kits are available in four Alexa Fluor® colors (or biotin) and supply everything needed for three labeling and separation reactions.

Important Features of Microscale Protein Labeling Kits:

• Labeled proteins typically ready to use typically in 2 hours (~30 minutes hands-on time)
• Optimized for 20–100 µg of protein with molecular weights between 12 and 150 kDa
• Purified using convenient spin filters with yields between 60 and 90%
• Stabilizing proteins must be removed from the sample before labeling


Stable Reaction Chemistry and Superior Alexa Fluor® Dyes
In this Microscale Protein Labeling Kit, the reactive label contains a succinimidyl (NHS) ester moiety that reacts with primary amines of proteins to form stable dye-protein conjugates. 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™ 555 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.

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

Biotin-XX Microscale Protein Labeling Kit with FluoReporter™ Biotin Quantitation Assay Kit (Invitrogen™)

Microscale Protein Labeling Kits provide a convenient means for attaching a fluorescent label to a small amount of antibody or protein (20–100 μg). The kits are available in four Alexa Fluor® colors (or biotin) and supply everything needed for three labeling and separation reactions.

Important Features of Microscale Protein Labeling Kits:

• Labeled proteins typically ready to use typically in 2 hr (~30 min hands-on time)
• Optimized for 20–100 μg of protein with molecular weights between 12 and 150 kDa
• Purified using convenient spin filters with yields between 60 and 90%
• Stabilizing proteins must be removed from the sample before labeling


Stable Reaction Chemistry and Superior Alexa Fluor® Dyes
In the Microscale Protein Labeling Kits, the reactive dye contains a tetrafluorophenyl (TFP) ester moiety that is more stable in solution than the commonly used succinimidyl (NHS) ester. TFP esters react efficiently with primary amines of proteins to form stable dye–protein conjugates. 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™ 568 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.

EZ-Link™ NHS-PEG4 Biotinylation Kit (Thermo Scientific™)

The Thermo Scientific EZ-Link NHS-PEG4 Biotinylation Kit contains EZ-Link NHS-PEG4-Biotin and accessory reagents required for 8 1–10 mg protein labeling reactions. EZ-Link NHS-PEG4-Biotin is a pegylated, water-soluble reagent for simple and efficient biotin labeling of antibodies, proteins and other primary amine-containing macromolecules.

Features of EZ-Link NHS-PEG4-Biotin:

Protein labeling—biotinylate antibodies or other proteins for detection or purification using streptavidin probes or resins
Amine-reactive—reacts with primary amines (-NH2), such as the side-chain of lysines (K) or the amino-termini of polypeptides
Pegylated – spacer arm contains a hydrophilic, 4-unit, polyethylene glycol (PEG) group
Enhances solubility – pegylation imparts water solubility to the biotinylated molecule, helping to prevent aggregation of biotinylated antibodies stored in solution
Irreversible—forms permanent amide bonds; spacer arm cannot be cleaved
Long reach – spacer arm (total length added to target) is 29 angstroms; this reduces steric hindrance when binding to avidin molecules

NHS-PEG4-Biotin is a long (29.0Å), pegylated, water-soluble, NHS-ester biotinylation reagent to label amines and maximize solubility of antibodies and other proteins. The N-hydroxysuccinimide ester (NHS) group reacts specifically and efficiently with lysine and N-terminal amino groups to form stable amide bonds. The hydrophilic polyethylene glycol (PEG) spacer arm imparts water solubility that is transferred to the biotinylated molecule, thus reducing aggregation of labeled proteins stored in solution. The PEG spacer arm also gives the reagent a long and flexible connection to minimize steric hindrance for binding to avidin molecules.

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™ NHS-PEG4-Biotin
EZ-Link™ Micro NHS-PEG4-Biotinylation Kit

FluoReporter™ Biotin Quantitation Assay Kit, for biotinylated proteins (Invitrogen™)

The FluoReporter® Biotin Quantitation Assay Kit provides a sensitive fluorometric assay for determining the number of biotin labels on nucleic acid samples (i.e., cDNA). The assay uses Biotective™ Green reagent, which contains a fluorescent dye that is quenched by ligands occupying the biotin binding sites. In the presence of biotin, the quencher dye ligands are displaced and fluorescence occurs. The fluorescence is proportional to the amount of added biotin. The results can be read with any fluorescence-based microplate reader capable of detecting FITC dye.

Important Features of FluoReporter® Biotin Quantitation Assay Kits:
• Can detect from 4 to 80 picomoles of biotin in a sample (50-fold higher sensitivity than HABA biotin-binding assay)
• Can be applied to as little as 13 ng of biotin-labeled nucleic acid (more is needed for lower degrees of labeling)
• Excitation/emission maxima of the reagent is 495/519 nm
• Supplied with a biotinylated positive control for standard curve


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

Click-IT™ O-GlcNAc Enzymatic Labeling System (Invitrogen™)

The Click-iT® O-GlcNAc Enzymatic Labeling System provides a highly sensitive and efficient method for the in-vitro modification of O-GlcNAc modified proteins. Proteins are enzymatically labeled utilizing the permissive mutant β-1,4-galactosyltransferase (Gal-T1 (Y289L)) which transfers azido-modified galactose (GalNAz) from UDP-GalNAz to O-GlcNAc residues. Then, 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). Labeling and detection can be completed in less than 24 hours and the Click-iT® glycoprotein products are compatible with LC-MS/MS and Multiplexed Proteomics™ technologies for in-depth analyses of this important post-translational modification.