Synthesis of an Isoglutathione Derivative by Proteases and Its α→γ Transpeptidation

Abstract

Benzyloxycarbonyl-L-cysteine and glycine benzhydrylamide were condensed by papain in a yield of 39.5%. After elimination of the N-protecting group, L-cysteinylglycine benzhydrylamide was condensed with benzyloxycarbonyl-L-glutamic acid by acid protease from Irpex lacteus Fr. in a yield of 21.0%. From the isoglutathione derivative thus obtained, αγ-linkage between glutamic acid and cysteine was formed by α→γ transpeptidation in alkaline conditions after esterification of γ-carboxylic acid.