Cy3 NHS Ester

Cyanine 3(Cy3) is a sulfonated polymethine dye, suitable for labeling biomolecules such as peptides, proteins, and nucleic acids for subsequent analysis.

Cyanine 3 (Cy3) is a chemically synthesized polymethine dye belonging to the cyanine fluorescent dye family. Cyanine dyes exist in non-sulfonated and sulfonated forms with nearly identical spectral properties, allowing interchangeable use in biomolecule labeling. The key advantage of sulfonated cyanines is their high water solubility, which removes the need for organic cosolvents in aqueous labeling reactions and reduces dye aggregation, thereby improving labeling efficiency. The Cy3 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.

Cy3 NHS Ester is a bright, water-soluble, orange-fluorescent dye used for labeling proteins and other molecules with an amine reactive group. This Cy3 is a sulfonated dye readily soluble in water. Its excitation maximum is 555 nm, and emission maximum is 565 nm. It demonstrates strong fluorescence intensity, excellent photostability, and minimal sensitivity to pH, making it suitable for fluorescence imaging and other fluorescence-based biological analyses.