Cyclic AMP-dependent inactivation of human liver pyruvate kinase

Abstract

Human liver pyruvate kinase is rapidly (within 2 min) inactivated by incubation of a human liver supernatant with cyclic AMP, when measured at suboptimal substrate concentrations. Half-maximal inactivation is reached with 0.04 μM cyclic AMP. The apparent K0.5 for phosphoenolpyruvate shifts from 0.5 mM to 1.1 mM by incubation with cyclic AMP. It is concluded that cyclic AMP-dependent protein kinase may catalyze the phosphorylation of human liver pyruvate kinase in vivo.