Resolution, Purification and Some Properties of Three Glutathione Transferases from Rat Liver Mitochondria

Abstract

From the matrix of rat liver mitochondria, 3 GSH [glutathione] transferases were isolated and named transferase 1, 2.1 and 2.2. Transferases 1 and 2.2 were purified to electrophoretic homogeneity. Transferase 1 contributes up to about 90% of the total mitochondrial GSH-transferring activity. It has a MW of approximately 45,000 and is composed of 2 subunits of similar size. The isoelectric point is at pH 7.1-7.4. Km values for GSH 1-chloro-2,4-dinitrobenzene are 0.3 and 0.7 mmol/l, respectively. Transferase 2.2 has the same MW and subunit structure like the transferase 1 and an isoelectric point at pH 4.8. Apparent Km values for GSH and 1-chloro-2,4-dinitrobenzene are 0.3 mmol/l and 0.4 mmol/l, respectively. Transferase 2.1 contributes only 1% of the total mitochondrial GSH-transferring activity. It has high apparent Km values for GSH and 1-chloro-2,4-dinitrobenzene (5.6 mmol/l and 1.3 mmol/l, respectively) and a limited spectrum of substrates.