EFFECTS OF GAMMA-GLUTAMYLCYSTEINE ETHYL-ESTER ON HEART MITOCHONDRIAL CREATINE-KINASE ACTIVITY - INVOLVEMENT OF SULFHYDRYL-GROUPS

To study the mechanism of the protective effect of gamma-glutamylcyste ine ethyl eater, mitochondrial creatine kinase activity of rat heart w as measured. gamma-Glutamylcysteine ethyl ester had a protective effec t against the depression of creatine kinase activity induced by xanthi ne + xanthine oxidase or hydrogen peroxide. gamma-Glutamylcysteine eth yl ester also prevented the depression of creatine kinase activity ind uced by N-ethylmaleimide. It is suggested that the protective effect o f gamma-glutamylcysteine ethyl ester is related to oxygen free radical s or to reduction of the sulfhydryl groups of the enzyme which were pr eviously oxidized by oxygen free radicals. (C) 1998 Elsevier Science B .V. All rights reserved.