Purification and properties of the pyruvate kinase of sturgeon muscle

Pyruvate kinase was purified from sturgeon muscle in yeilds comparable with those obtained from the muscles of other species. In contrast with mammalian muscle pyruvate kinase the enzyme from sturgeon muscle gives a sigmoidal velocity curve with respect to phosphoenolpuruvate saturation, is activated by fructose 1.6-diphosphate, and is inhibited by bivalent copper ions. In these respects it is similar to the enzyme isolated from mammalian liver. The degree of interaction between phosphoenolpyruvate-binding sites is dependent on temperature.