Fluorescence and structure of proteins as measured by incorporation of fluorophore. II. Synthesis of maleimide derivatives as fluorescence-labeled protein-sulfhydryl reagents.

Abstract

A novel approach to studies of structure and function of proteins utilizing fluorescencelabeled specific reagent is proposed. N-[p-(2-Benzoxazolyl) phenyl] maleimide (IIIa) and N-[p-(2-benzthiazolyl) phenyl] maleimide (IIIb) were synthesized as sulfhydryl reagents of this type and the addition reaction with cysteine ester was investigated. Cyclization of maleamic acids with PPA is demonstrated to be a good method for synthesis of N-substituted maleimides.