Cyanine5 NHS ester chloride is a reactive dye with red fluorescence that requires a small amount of organic cosolvent (such as DMF or DMSO) to label amino groups in peptides, proteins, and oligonucleotides.

Anthocyanin-5 NHS ester amine reactive red fluorescent dyes are used to react with free amino groups on cysteine amino acids, which are present in terminal peptides for end-wrapped polybeta-amino ester (pBAEs) skeletons [1] .

Cyanine5 NHS ester chloride fluorescent labeling experiment
Operation steps:
a. Weigh Cyanine5 NHS ester chloride to prepare a 2 mg/mL methanol solution, take 300 μL and add the substrate to be labeled;
b. Gradually add 10 mL of deionized water under high-speed stirring, and react at room temperature in the dark for 2 h;
c. After centrifugation and washing, the Cy5-labeled fluorescent material is obtained and stored at 4°C for later use.