Dansyl amide is a fluorescent probe for albumin and CAII.1,2 It binds to serum albumin and carbonic anhydrase II (CAII; Kds = 7.57 and 0.2 ?M, respectively) and has been used to determine ligand affinities for these proteins. Dansyl amide binding to CAII results in an increase in fluorescence due to FRET from nearby active site tryptophan residues and displays excitation/emission maxima of 280/470 nm, respectively, when bound to CAII and a decrease in fluorescence can be used to quantify CAII ligand binding.2
1.Epps, D.E., Raub, T.J., and Kézdy, F.J.A general, wide-rage spectrofluorometric method for measuring the site-specific affinities of drugs toward human serum albuminAnal. Biochem.227(2)342-350(1995) 2.Wang, S.C., and Zamble, D.B.Fluorescence analysis of sulfonamide binding to carbonic anhydraseBiochem. Mol. Biol. Educ.34(5)364-368(2006)