[Partial purification and certain properties of gamma-glutamyltransferase from rat liver and hepatoma]

gamma-Glutamyltransferase (GGT) from the liver and transplantable hepatoma of rats was purified 130- and 170-fold, respectively. The properties of the enzymatic preparations obtained were studied. The optimum pH for the transferase reaction between L-gamma-glutamyl-p-nitroanilide (5 mM) and glycyl-glycine (50 mM) was 8.0--8.2, while that for the auto-transferase reaction (without glycyl-glycine) amounted to 9.3--9.5. The isoelectric points of GGT from the liver correlated with the pH 3.9, 4.2 and 4.4 whereas those of hepatoma enzyme with the pH 5.7, 6.0 and 7.0 GGT obtained from both sources were equally specific for various acceptors at the pH 8.1 and 7.0. It has been shown that metotrexate (0.9 mM) and folic acid (3.5 mM) inhibited both enzymes by 50%.