Author's Organization：Faculty of Pharmaceutical Sciences, University of Tokyo Faculty of Pharmaceutical Sciences, University of Tokyo Faculty of Pharmaceutical Sciences, University of Tokyo Dental Engineering, Tokyo Medical and Dental University
A fluorescent Koshland reagent, 2-carboxy-1-hydroxy-4-naphthylmethyldimethylsulfonium chloride (I), was newly synthesized. I rapidly reacts with tryptophan under mild condition to give a fluorescent adduct (λex=255 nm, λem=416 nm). I was applicable to the modification of bovine serum albumin molecule and the calculation of the number of its tryptophan residues.
