Cyanine5 NHS ester iodide is a red emitting fluorescent dye for labeling of amino-groups in peptides, proteins, and oligonucleotides[1].
Cyanine-5 NHS ester amine-reactive red emitting fluorescent dye is used to react with the free amino group on the cysteine amino acid present in terminal peptides used for end-capping Poly(β-amino esters) (pBAEs) backbones[1].
Reference:
[1]. Brugada-Vilà P, et al. Oligopeptide-modified poly(beta-amino ester)s-coated AdNuPARmE1A: Boosting the efficacy of intravenously administered therapeutic adenoviruses. Theranostics. 2020;10(6):2744-2758.