4-{[4-(Dimethylamino)-phenyl]-azo}-benzoic acid-[3- (iodoacetamido)-propyl]-amide / DABCYL-IAA

4-[[4-(Dimethylamino)-phenyl]azo]-benzoesäure-[3-(iodacetamido)- propyl]-amide is a non-fluorescent FRET quencher.

It readily reacts with the thiol group found on cysteine or with thiol-modified oligonucleotides to form a stable carbon-sulfur bond. DABCYL is a non-fluorescent dye molecule which efficiently quenches a variety of fluorescent dyes and is therefore one of the most widely utilized acceptors for FRET-based nucleic acid probes and protease substrates.