Lack of temperature-sensitivity of rat liver pyruvate kinase

Rat liver pyruvate kinase, prepared by Sephadex treatment of a 10(5)g supernatant in phosphate buffer, is quite stable and gives reproducible results when a variety of parameters are altered in the enzyme assay. Incubation of this preparation at 25 degrees C or 0-2 degrees C has no effect on the activation by fructose 1,6-diphosphate or inhibition by ATP or alanine.