Fluorescein NHS Antibody Labeling Kit

The fluorescein labeling kits are high-performance derivatives of fluorescein dye, activated for easy and reliable labeling of antibodies, proteins and other molecules for use as fluorescent probes.
Fluorescein dyes are used in wide-ranging applications including fluorescence microscopy, flow cytometry and immunofluorescence-based assays such as Western Blotting and ELISA. Fluorescein NHS are reactive toward primary amine groups on proteins, peptides and other biomolecules, while fluorescein--maleimide react with free sulfhydryl on cysteine residues.

Most activated fluorescein derivatives are mixtures of isomers with reactive groups attached at the 5- and 6-positions of the bottom ring. There is a big difference in flow cytometry although it is a small difference in the properties of these isomers in terms of excitation and emission spectra. The small difference will make your assay complicated because the ratio of two isomers varies lot by lot.
BroadPharm fluorescein labeling kits use single isomer- 6-isomer NHS and Maleimade to solve the issues.

• Amine and thio-specific labeling: the NHS-ester and maleimide efficiently labels antibodies and other purified proteins at primary amines or thiol.
• Optimized procedure: following the standard protocol results in antibodies with excellent dye:protein ratios for optimum activity and fluorescence
• Single-use fluors: no need to weigh tiny amounts powder; kits contain single-use vials of reagent
• Efficient purification: kits include purification resin and easy-to-use spin columns, ensuring rapid and efficient removal of non-reacted dye and excellent protein recovery.

* single isomer, no lot-to-lot variability.