A new fluorescent sulfhydryl reagent N-(9-acridinyl)maleimide

Abstract

N- (9-Acridinyl) maleimide (NAM) was synthesized as a new fluorescent sulfhydryl reagent. This reagent when combined with thiols exhibits strong fluorescence with the emission maximum at 426 nm, being excited at 362 nm, whereas the reagent itself emits practically no fluorescence. The addition reaction with cysteine was investigated at various pH (3.06.0). Fluorometric determination of the thiol and disulfide compounds in the range of 0.4 × 10^-616 × 10^-6 M could be performed very simply by using NAM.
All the other amino acids did not react with NAM; this reagent seems to react selectively with thiol group.