Label antibodies and other proteins with bright alternatives to Alexa Fluor*, CyDye* and LI-COR* Fluorescent Dyes.

Thermo Scientific Amine-Reactive DyLight Dyes are NHS ester-activated derivatives of high-performance DyLight Fluors for fluorescent labeling of antibodies and other proteins to be used as molecular probes for cellular imaging and other fluorescence detection methods.

The selection of activated DyLight Fluors have absorption spectra ranging from 350nm to 777nm, with emission profiles that are compatible with the principal detection wavelengths of common fluorescence instrumentation. The DyLight Fluors have high fluorescence intensity over a broad pH range (pH 4–9) and are more photostable than CyDye*, Alexa Fluor*, and LI-COR* Dyes in many applications. The high water solubility of the DyLight Fluors allows a high dye-to-protein ratio to be achieved without causing precipitation of the conjugates.

All amine-reactive DyLight Dyes are activated with an N-hydroxysuccinimide (NHS) ester moiety to form a reactive acylating reagent. Protein labeling occurs through reaction of the NHS ester-activated dye with exposed N-terminal α-amino groups or the ε-amino groups of lysine residues to form stable amide bonds. Reactions with other nucleophiles can occur, but will not result in stable conjugation. (Learn more about NHS ester chemistry.)

Typical labeling reactions require the DyLight Dyes to first be dissolved in anhydrous dimethyl formamide (DMF) or other 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 Reactive Dyes to be provided in multiple formats with flexible protocols to achieve efficient degrees of labeling.

Highlights of Amine-reactive DyLight Fluorophores:

• Specific reaction chemistry – choose NHS ester-activated DyLight Dyes to specifically label proteins and other molecules at primary amines (-NH2); learn more about NHS-ester reactions
• Efficient labeling methods – well-characterized chemistries and optimized protocols provide for reliable, high-quality labeling
• High water solubility – together with convenient package sizes, this feature provides for easy reagent reconstitution and flexible reaction conditions

General DyLight Fluorophore Highlights:

• Bright fluorescence – intense emission provides superior sensitivity and requires less conjugate
• Narrow emission spectra – negligible bleed-through between fluorophore channels enables multi-color detection
• Excellent photostability – exceptional resistance to photobleaching enables fluorescence imaging under the most demanding conditions (e.g., structured illumination, 4Pi microscopy)
• Buffer stability – conjugated fluorophores are completely stable at pH 4-9
• Instrument compatibility – excitation and emission spectra correspond with filter sets and laser settings of all popular fluorescence instrumentation

Emission spectra of Thermo Scientific DyLight Fluors 350-800. Line colors represent the approximate visible colors of the wavelength maxima. Learn more... DyLight Dye spectral properties (opens new window)

Related Products and Resources:

• Complete DyLight Fluor Product Guide
• All Fluorescent Labeling Reagents and Kits
• DyLight Fluor Secondary Antibody Conjugates
• DyLight Fluor Streptavidin and NeutrAvidin Conjugates
• DyLight Fluorescent Western Blotting Kits and Fluorescent MW Markers
• Krypton Fluorescent Protein Stains

* Trademark; see link in page footer.