QSY-9-succinimidyl ester

QSY-9-succinimidyl ester is a non-fluorescent acceptor molecule featuring a terminal NHS ester group. Its quenching range is broad and intense, spanning 500-600 nm, which makes it suitable as an acceptor for fluorescence resonance energy transfer (FRET) applications with fluorescent dyes in the same wavelength range. The NHS ester can label primary amines (-NH2) on proteins, amine-modified oligonucleotides, and other amine-containing molecules.