Dansylamide

Dansylamide (DNSA) is a fluorescent dye that forms in a reaction between dansyl chloride and ammonia. Dansylamide is widely used in biochemistry and chemistry to label substances with the fluorescent dansyl group. The dansyl group can be introduced into amino acids or other amines. The excitation maximum (350 nm) is essentially independent on the medium, whereas the emission maximum strongly depends on the solvent and varies from 520 to 550 nm. The fluorescent dye dansylamide selectively interacts with the binding site I of human serum albumin (HSA). Changes in probe fluorescence can be analyzed by fluorescence titrations as a result of competitive displacement by drugs and pharmaceuticals. Dansylamide can also be used as an active site probe for carbonic anhydrase and as an effective acceptor in FRET probes to quantify protein fluorescence. Dansylamide is also used as building block or intermediate in synthesis of fluorescent dyes.