Javier Nieto Gutiérrez

CoAS-Sglutathione and GSSG reductases from rat liver: Two disulfide oxidoreductase activities in one protein entity

Abstract The characteristics of the NADPH-dependent CoAS-Sglutathione reductase from rat liver have been studied. In contrast to the enzyme obtained from yeast during the purification procedure using different types of column chromatography and isoelectric-focusing technique, the new reducing enzyme in rat liver was found to purify together with GSSG reductase. The data indicate that in liver both enzymatic activities belong to the same protein entity, since they cannot be separated by any of the above regular physical methods. The CoAS-Sglutathione and GSSG reducing activities have a molecular weight of 42 500; a pI of 6.85 and do not reduce cystine, cystamine, pantethine or insulin. On the other hand, an NADPH-dependent non-specific disulfide reductase also present in rat liver extracts can be easily separated and distinguished from the GSSG and CoAS-Sglutathione-reducing enzymes by ion-exchange column chromatography and isoelectric-focusing.