Glycine metabolism by rat liver mitochondria: IV. Isolation and characterization of hydrogen carrier protein, an essential factor for glycine metabolism

Abstract

Two protein fractions were isolated from rat liver mitochondria which, when combined, catalyzed the synthesis of glycine from l-serine, ammonia, and bicarbonate. These fractions also catalyzed the cleavage of glycine and the exchange of the glycine carboxyl group with bicarbonate. One of the protein fractions, tentatively called “carboxylation enzyme”, was purified partially and the other protein, called “hydrogen carrier protein”, was obtained in an apparently pure form. Hydrogen carrier protein obtained was homogeneous on disc electrophoresis and its molecular weight was about 17,000 as judged from Sephadex chromatography. Per molecule it contained one disulfhydryl entity whose sulfhydryl groups were found to participate in electron transport during glycine metabolism.