Changes in some properties of the aurochs heart pyruvate dehydrogenase complex induced by its partial phosphorylation.

Comparative studies on the properties of the dephosphorylated and partially phosphorylated (to 35% activity reduction) pyruvate dehydrogenase complex (PDC) from aurochs heart muscle have been made. Data have been obtained indicating that the partial phosphorylation of PDC abolishes the kinetic attributes of a positive cooperativity of the pyruvate binding sites (nH = 1.5) featuring at low substrate concentrations. In addition, the partially phosphorylated PDC is inactivated slower at 50 degrees C.