Evidence for Participation of Vit. B6 in Glutamine-a-Keto Acid Transamination-Deamidation Reaction

Abstract

Summary1. Liver homogenates prepared from rats given large doses of isonicotinic acid hydrazide (INAH) exhibited reduced glut-aminepyruvate transaminase-deamidase activity and increased glutaminase activity. 2. Purified enzyme preparations (free of glutaminase) prepared from livers of INAH-treated rats catalyzed the glutamine-pyruvate reaction at markedly reduced rates compared to controls. Addition of pyridoxal (or pyri-doxamine) phosphate produced a considerable increase in activity of the preparations obtained from INAH-treated rats, but not of that of the untreated controls. 3. The evidence supports the concept that vit. B6 participates in the glutamine transaminase system.