“…All enzyme assays were demonstrated to be linear with time and with protein concentration. The marker enzymes assayed were: y-glutamyltranspeptidase (Tate & Meister, 1974), alkaline phosphatase (Scholer & Edelman, 1979), phosphoenolpyruvate carboxykinase (Seubert & Huth, 1965), ,J-glucuronidase ) (measured at 37°C); succinateand NADPH-cytochrome c reductase (Sottocassa et al, 1967), lactate dehydrogenase (Morrison et al, 1966) and hexokinase (Vinuela et al, 1963), measured at room temperature. We assayed four enzymes of arginine metabolism: argininosuccinate synthase, argininosuccinate lyase, arginase and orthinine aminotransferase.…”