Glutamate Oxaloacetate Transaminase is a pyridoxal phosphate-dependant enzyme which exists in two isoenzymes; mitochondrial and cytosolic forms. The enzyme plays an important role in amino acid metabolism and in the urea and tricarboxylic acid cycles. In liver about 80% of the enzyme activity is mitochondrial in origin, whereas in serum the enzyme activity is largely cytosolic. In hepatic disease, serum levels are used to assess liver necrosis and for determining prognosis. In patient with acute Myocardial infarction, measurment of AST isoenzymes provides diagnostic information that differs from that obtained by determination of other marker proteins