Cy5 NHS Ester

Cyanine 5 (Cy5) is a chemically synthesized polymethine dye, suitable for labeling biomolecules such as peptides, proteins, and nucleic acids.

Cyanine 5 (Cy5) is a chemically synthesized polymethine dye belonging to the cyanine fluorescent dye family. Cyanine dyes are available in non-sulfonated and sulfonated forms, which exhibit nearly identical spectral characteristics and are therefore interchangeable in most applications, including the labeling of biomolecules such as DNA and proteins. The primary distinction between these two forms is that sulfonated cyanines are highly water-soluble, eliminating the need for organic cosolvents in aqueous labeling reactions and reducing dye aggregation, which improves labeling efficiency. The Cy5 NHS ester contains an N-hydroxysuccinimide–activated group that reacts efficiently with amino groups on biomolecules, particularly primary amines, forming stable amide bonds for covalent labeling of peptides, proteins, and nucleic acids.

Cyanine5 NHS ester is a reactive dye for labeling amino groups in peptides, proteins, and oligonucleotides, typically requiring only minimal amounts of organic cosolvent in aqueous labeling reactions. This Cy5 is provided as a sulfonated dye that dissolves readily in water, with an excitation maximum at 649 nm and an emission maximum at 670 nm. It exhibits strong fluorescence intensity, high photostability, and minimal sensitivity to pH, making it well suited for fluorescence imaging and other fluorescence-based biological assays.