NATURE OF ENZYMATIC REDUCTION OF S-SULFOGLUTATHIONE IN LIVER AND PEAS

The NADPH-dependent enzymatic reduction of S-sulfoglutathione (GSSO3H) in liver and peas has been reexamined. Previous reports have indicated that this reaction is catalyzed by a reductase distinct from glutathione reductase. We present evidence, however, that the reduction is due to an initial reaction of GSSO3H with glutathione (GSH), followed by reduction of the glutathione disulfide (GSSG) formed by glutathione reductase and NADPH. This conclusion is based on the finding that the GSSO3H-reducing activity of a homogenate is lost upon either dialysis or gel filtration and is completely regained by adding GSH. The reconstitution was equally efficient in an extensively purified glutathione reductase as in a crude dialyzed tissue supernatant. We have evidence that the reaction between GSSO3H and GSH is catalyzed by a transhydrogenase found in rat liver. © 1969.