Purification and properties of the pyruvate kinase isoenzymes type L and M2 from chicken liver.

A procedure for the simultaneous purification of both isoenzymes of pyruvate kinase (type M2 and L) from chicken liver has been worked out. Each isoenzyme produces a single band in dodecylsulfate gel electrophoresis. Each has a molecular weight of 190 000 and contains four apparently identical subunits of Mr = 50 000. The isoenzymes differ in their isoelectric points (type L: 6.3; type M2: 8.3) and their kinetic behaviour. Pyruvate kinase type L had an S-shaped phosphoenolpyruvate saturation curve (K 0.5=0.79 mM) which was transformed into an hyperbola in the presence of fructose 1,6-bisphosphate, while type M2 had a phosphoenolpyruvate saturation curve of the Michaelis-Menten type (K0.5=0.2mM). Antibodies against pyruvate kinase type L from chicken liver inactivated type L from rat and partially inactivated type M2 from chicken and rat; but the antibodies against type L did not react with type M1 from chicken breast muscle. It is therefore concluded that, contrary to a previous report (Strandholm, J.J. et al. (1975) Biochemistry 14, 2242-2246), avian liver contains pyruvate kinases type M2 and L as the mammalian liver does.