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Alexa Fluor™ 633 Carboxylic Acid, tris(triethylammonium) salt (Invitrogen™)

Alexa Fluor® 633 Carboxylic Acid is a non-reactive form of Alexa Fluor® 633 that can be used as a reference standard for dye-conjugates. Additionally, this carboxylic acid derivative can be converted to an amine-reactive ester using standard chemical techniques or coupled to hydrazines, hydroxylamines, and amines in aqueous solution using water-soluble carbodiimides such as EDAC (Cat. No. E2247).

Characteristics of Alexa Fluor® 633 dye include:

• Laser line: 633 or 635 nm
• Excitation maxima: 632 nm
• Emission maxima: 647 nm

More About Alexa Fluor® 633 Dye
The Alexa Fluor 633 dye and its conjugates are a perfect match to the 633 nm spectra line of the He-Ne laser or the 635 nm spectral line of red diode lasers. This and other far-red fluorescent Alexa Fluor® dyes are important labels for fluorescence imaging because their spectra are beyond the range of most sample autofluorescence.

Discover the Benefits of the Alexa Fluor® Dye Series
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 in the Molecular Probes Handbook.

Alexa Fluor™ 488 Carboxylic Acid, tris(triethylammonium) salt (Invitrogen™)

Alexa Fluor® 488 Carboxylic Acid is a non-reactive form of Alexa Fluor® 488 that can be used as a reference standard for dye-conjugates. Additionally, this carboxylic acid derivative can be converted to an amine-reactive ester using standard chemical techniques or coupled to hydrazines, hydroxylamines, and amines in aqueous solution using water-soluble carbodiimides such as EDAC (Cat. No. E2247).

Characteristics of Alexa Fluor® 488 dye include:

• Laser line: 488 nm
• Common filter set: FITC (fluorescein)
• Excitation maxima: 500 nm
• Emission maxima: 525 nm

More About Alexa Fluor® 488 Dye
Alexa Fluor® 488 dye is a bright, green-fluorescent dye with excitation ideally suited to the 488 nm laser line. It is the brightest and most photostable green dye for sensitive detection in live or fixed cells. Alexa Fluor® 488 dye is commonly used with DAPI, and Alexa Fluor® 594 and 647 dyes for multiplexing. Learn more about this dye and related products.

Discover the Benefits of the Alexa Fluor® Dye Series
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 in the Molecular Probes Handbook.

Alexa Fluor™ 647 Carboxylic Acid, tris(triethylammonium) salt (Invitrogen™)

Alexa Fluor® 647 Carboxylic Acid is a non-reactive form of Alexa Fluor® 647 that can be used as a reference standard for dye-conjugates. Additionally, this carboxylic acid derivative can be converted to an amine-reactive ester using standard chemical techniques or coupled to hydrazines, hydroxylamines, and amines in aqueous solution using water-soluble carbodiimides such as EDAC (Cat. No. E2247).

Characteristics of Alexa Fluor® 647 dye include:

• Laser line: 647 nm
• Common filter set: Cy® 5
• Excitation maxima: 650 nm
• Emission maxima: 665 nm

More About Alexa Fluor® 647 Dye
Alexa Fluor® 647 dye is a bright, far-red-fluorescent dye with excitation ideally suited for the 594 nm or 633 nm laser lines. It is ideal for imaging low-abundance targets, especially in fixed cells. Alexa Fluor® 647 dye is commonly used with DAPI, and Alexa Fluor® 488 and 594 dyes for multiplexing. Learn more about this dye and related products.

Discover the Benefits of the Alexa Fluor® Dye Series
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 in the Molecular Probes Handbook.

Alexa Fluor™ 532 Carboxylic Acid, triethylammonium salt (Invitrogen™)

Alexa Fluor® 532 Carboxylic Acid is a non-reactive form of Alexa Fluor® 532 that can be used as a reference standard for dye-conjugates. Additionally, this carboxylic acid derivative can be converted to an amine-reactive ester using standard chemical techniques or coupled to hydrazines, hydroxylamines, and amines in aqueous solution using water-soluble carbodiimides such as EDAC (Cat. No. E2247).

Characteristics of Alexa Fluor® 532 dye include:

• Laser line: 532 nm
• Excitation maxima: 530 nm
• Emission maxima: 554 nm

More About Alexa Fluor® 532 Dye
The Alexa Fluor® 532 dye and its conjugates have excitation and emission spectra that are intermediate between those of the green-fluorescent Alexa Fluor 488 dye and the orange-fluorescent Alexa Fluor 546 dye, making it an ideal dye for use with 532 excitation sources, including the frequency-doubled Nd-Yag laser.

Discover the Benefits of the Alexa Fluor® Dye Series
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 in the Molecular Probes Handbook.

Alexa Fluor™ 555 Carboxylic Acid, tris(triethylammonium) salt (Invitrogen™)

Alexa Fluor® 555 Carboxylic Acid is a non-reactive form of Alexa Fluor® 555 that can be used as a reference standard for dye-conjugates. Additionally, this carboxylic acid derivative can be converted to an amine-reactive ester using standard chemical techniques or coupled to hydrazines, hydroxylamines, and amines in aqueous solution using water-soluble carbodiimides such as EDAC (Cat. No. E2247).

Characteristics of Alexa Fluor® 555 dye include:

• Laser line: 488 or 532 nm
• Common filter set: TRITC (tetramethylrhodamine)
• Excitation maxima: 555 nm
• Emission maxima: 580 nm

More About Alexa Fluor® 555 Dye
Alexa Fluor® 555 dye is a bright, orange-fluorescent dye that can be excited using the 488 nm or 532 nm laser lines. It is a recommended replacement for Cy®3 dye or tetramethylrhodamine, with greater photostability than Cy®3 dye in live and fixed cells. Alexa Fluor® 555 dye is commonly used with DAPI, and Alexa Fluor® 488 and 647 dyes for multiplexing. Learn more about this dye and related products.

Discover the Benefits of the Alexa Fluor® Dye Series
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 in the Molecular Probes Handbook.

Alexa Fluor™ 750 Carboxylic Acid, tris(triethylammonium) salt (Invitrogen™)

Alexa Fluor® 750 Carboxylic Acid is a non-reactive form of Alexa Fluor® 750 that can be used as a reference standard for dye-conjugates. Additionally, this carboxylic acid derivative can be converted to an amine-reactive ester using standard chemical techniques or coupled to hydrazines, hydroxylamines, and amines in aqueous solution using water-soluble carbodiimides such as EDAC (Cat. No. E2247).

Characteristics of Alexa Fluor® 750 dye include:

• Laser line: 750 nm
• Common filter set: Cy® 7
• Excitation maxima: 749 nm
• Emission maxima: 775 nm

More About Alexa Fluor® 750 Dye
Alexa Fluor® 750 dye and its conjugates exhibit fluorescence spectra that are very similar to those of CY® 7 dye. Its fluorescence emission maximum at 775 nm is well separated from commonly used far-red fluorophores such as Alexa Fluor® 647 or allophycocyanin (APC), facilitating multicolor analysis.

Discover the Benefits of the Alexa Fluor® Dye Series
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 in the Molecular Probes Handbook.

Alexa Fluor™ 594 Carboxylic Acid, tris(triethylammonium) salt (Invitrogen™)

Alexa Fluor® 594 Carboxylic Acid is a non-reactive form of Alexa Fluor® 594 that can be used as a reference standard for dye-conjugates. Additionally, this carboxylic acid derivative can be converted to an amine-reactive ester using standard chemical techniques or coupled to hydrazines, hydroxylamines, and amines in aqueous solution using water-soluble carbodiimides such as EDAC (Cat. No. E2247).

Characteristics of Alexa Fluor® 594 dye include:

• Laser line: 561 or 594 nm
• Common filter set: Texas Red
• Excitation maxima: 590 nm
• Emission maxima: 617 nm

More About Alexa Fluor® 594 Dye
Alexa Fluor® 594 dye is a bright, red-fluorescent dye that can be excited using the 561 or 594 nm laser lines. It serves as a direct replacement for Texas Red® dye with bright signal and excellent photostability, especially in fixed cells. Alexa Fluor® 594 dye is commonly used with DAPI, and Alexa Fluor® 488 and 647 dyes for multiplexing. Learn more about this dye and related products.

Discover the Benefits of the Alexa Fluor® Dye Series
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 in the Molecular Probes Handbook.

Alexa Fluor™ 350 Carboxylic Acid, bis(triethylammonium) salt (Invitrogen™)

Alexa Fluor® 350 Carboxylic Acid is a non-reactive form of Alexa Fluor® 350 that can be used as a reference standard for dye-conjugates. Additionally, this carboxylic acid derivative can be converted to an amine-reactive ester using standard chemical techniques or coupled to hydrazines, hydroxylamines, and amines in aqueous solution using water-soluble carbodiimides such as EDAC (Cat. No. E2247).

Characteristics of Alexa Fluor® 350 dye include:

• Laser line: 350 nm
• Common filter set: DAPI
• Excitation maxima: 346 nm
• Emission maxima: 442 nm

More About Alexa Fluor® 350 Dye
Alexa Fluor® 350 dye is a blue-fluorescent dye with moderate photostability and excitation that matches the 350 nm laser line. As the brightest dye available in the blue channel, it is best used for high-abundance targets like actin or tubulin. Alexa Fluor® 350 dye is commonly used with Alexa Fluor® 488, 594, and 647 dyes for multiplexing. Learn more about this dye and related products.

Discover the Benefits of the Alexa Fluor® Dye Series
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 in the Molecular Probes Handbook.

Alexa Fluor™ 546 Carboxylic Acid, tris(triethylammonium) salt (Invitrogen™)

Alexa Fluor® 546 Carboxylic Acid is a non-reactive form of Alexa Fluor® 546 that can be used as a reference standard for dye-conjugates. Additionally, this carboxylic acid derivative can be converted to an amine-reactive ester using standard chemical techniques or coupled to hydrazines, hydroxylamines, and amines in aqueous solution using water-soluble carbodiimides such as EDAC (Cat. No. E2247).

Characteristics of Alexa Fluor® 546 dye include:

• Laser line: 546 nm
• Common filter set: TRITC (tetramethylrhodamine)
• Excitation maxima: 556 nm
• Emission maxima: 573 nm

More About Alexa Fluor® 546 Dye
Alexa Fluor® 546 dye is a bright, yellow-fluorescent dye that can be excited using the 488 nm or 532 nm laser lines. Alexa Fuor® 546 serves as an alternative for tetramethylrhodamine or Cy®3 dye, with higher initial intensity than Alexa Fluor® 555 dye, but lower photostability in buffer or antifade. Learn more about this dye and related products.

Discover the Benefits of the Alexa Fluor® Dye Series
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 in the Molecular Probes Handbook.

Alexa Fluor™ 568 Carboxylic Acid, tris(triethylammonium) salt (Invitrogen™)

Alexa Fluor® 568 Carboxylic Acid is a non-reactive form of Alexa Fluor® 568 that can be used as a reference standard for dye-conjugates. Additionally, this carboxylic acid derivative can be converted to an amine-reactive ester using standard chemical techniques or coupled to hydrazines, hydroxylamines, and amines in aqueous solution using water-soluble carbodiimides such as EDAC (Cat. No. E2247).

Characteristics of Alexa Fluor® 568 dye include:

• Laser line: 568 nm
• Common filter set: Texas Red
• Excitation maxima: 578 nm
• Emission maxima: 603 nm

More About Alexa Fluor® 568 Dye
Alexa Fluor® 568 dye is a bright, orange- or orange-red-fluorescent dye with excitation ideally suited for the 568 nm laser line on the Ar-Kr mixed-gas laser and matched well with RFP filter sets. Alexa Fluor® 568 dye is commonly used with DAPI, and Alexa Fluor® 488 and 647 dyes for multiplexing. Learn more about this dye and related products.

Discover the Benefits of the Alexa Fluor® Dye Series
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 in the Molecular Probes Handbook.

Alexa Fluor™ 546 C5 Maleimide (Invitrogen™)

Alexa Fluor® 546 is a bright, orange fluorescent dye that can be excited using the 488 nm or 532 nm laser lines. Used for stable signal generation in imaging and flow cytometry, Alexa Fluor® 546 dye is water soluble and pH-insensitive from pH 4 to pH 10. In addition to reactive dye formulations, we offer Alexa Fluor® 546 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® 546 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® 546 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® 546 dye
Reactive group: maleimide
Reactivity: thiol groups on proteins and ligands, oligonucleotide thiophosphates
Ex/Em of the conjugate: 554/570 nm
Extinction coefficient: 93,000 cm-1M-1
Spectrally similar dyes: Rhodamine red, Cy3
Molecular weight: 1034.37

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™ 546 NHS Ester (Succinimidyl Ester) (Invitrogen™)

Alexa Fluor® 546 is a bright yellow dye. Used in imaging and flow cytometry, Alexa Fluor® 546 dye is water soluble and pH-insensitive from pH 4 to pH 10. In addition to reactive dye formulations, we offer Alexa Fluor® 546 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 Alexa Fluor® 546 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® 546 dye
Reactive group: NHS ester
Reactivity: Primary amines on proteins and ligands, amine-modified oligonucleotides
Ex/Em of the conjugate: 554/570 nm
Extinction coefficient: 112,000 cm-1M-1
Molecular weight: 1159.6

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.

DyLight™ 530-R2 NHS Ester (Thermo Scientific™)

Label peptides, antibodies and other proteins at primary amines with the rhodamine-based, water-soluble Thermo Scientific DyLight Green-emitting Specialty Dye, which is comparable to Alexa Fluor 532.

DyLight Green-emitting Dye is a labeling agent that provides bright fluorescence detection for imaging. 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 penetration in vivo, while more hydrophilic dyes have less nonspecific binding potential. This dye contains 2 sulfonates for increased solubility and an amine-reactive NHS ester for simple modification of antibodies, proteins, peptides or other biomolecules through amide bond formation.

Features of DyLight 530-R2 NHS Ester:

NHS ester reactive group—allows immediate labeling of antibodies, proteins, peptides and other amine-containing molecules through amide bond formation
Water solubility—2 sulfonate groups increase the solubility of this dye over over less-sulfonated dyes

Applications:
• Imaging
• Antibody labeling
• Direct immunofluorescence staining
• Flow cytometry
• Fluorescence correlation spectroscopy
• ELISA
• Western blotting
• Protein microarrays
• Polymer labeling
• Peptide labeling
• Phalloidin labeling for actin staining

DyLight™ 800 NHS Ester (Thermo Scientific™)

Thermo Scientific DyLight 800 Amine-Reactive Dye is an NHS ester-activated derivative of high-performance DyLight 800 used to fluorescently label antibodies and other proteins that are then used as molecular probes for cellular imaging and other fluorescence detection methods.

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. DyLight 800 Amine-Reactive Dye is also available as part of two antibody labeling kit sizes.

Features of DyLight 800 NHS Ester:

High performance— DyLight 800 replaces Alexa Fluor 800 and IRDye 800 for near-infrared staining
Specific— NHS ester-activated dye labels proteins and other molecules at primary amines (-NH2)
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 800 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 800 Amine-Reactive Dye to be provided in multiple formats with flexible protocols to achieve efficient degrees of labeling.

We also offer Standard and Microscale DyLight 800 Antibody Labeling Kits for fast and efficient fluorescent labeling of antibodies for use in fluorescence 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 microscale kit contains all of the necessary components to perform five separate labeling reactions using 100 µg of IgG. Both kit sizes include the Amine-Reactive DyLight 800 NHS-ester in convenient single-use vials as well as purification resin and spin columns for the preparation of ready-to-use conjugate.

Related Products
DyLight™ 800 Antibody Labeling Kit
DyLight™ 800 Microscale Antibody Labeling Kit

DyLight™ 488 Maleimide (Thermo Scientific™)

Thermo Scientific DyLight 488 Sulfhydryl-Reactive Dye is a maleimide-activated derivative of high-performance DyLight 488 used to fluorescently label sulfhydryl-containing peptides, proteins, and other biomolecular probes.

DyLight 488 has high fluorescence intensity over a broad pH range (pH 4-9) and is more photostable than Cy2™ dye, Alexa Fluor™ 488, FITC, and LI-COR™ dyes in many applications. The high water solubility of DyLight Fluors allows a high dye-to-protein ratio to be achieved without causing precipitation of the conjugates.

Features of DyLight 488 Maleimide:

High performance—DyLight 488 shows brighter fluorescence than Alexa Fluor 488, FITC and Cy2 dye
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 488 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.