Effects of temperature on measurement of aspartate aminotransferase and alanine aminotransferase in commercial control sera.

The catalytic activity concentrations of aspartate aminotransferase (EC 2.6.1.1) and alanine aminotransferase (EC 2.6.1.2) in several commercial control sera were determined at three different temperatures. Although these sera were of various biological origins, the temperature-conversion factors calculated are nearly identical to those for native human sera. The proportional increase of the activity concentration caused by adding pyridoxal-5'-phosphate to the reaction mixture is independent of the reaction temperature. Arrhenius plots and some thermodynamic activation parameters of both enzymes are independent of the presence of the coenzyme pyridoxal-5'-phosphate.