Studies on the phosphorylation and dephosphorylation of L-type pyruvate kinase by the catalytic subunit of cyclic AMP-dependent protein kinase.

Abstract

Homogeneous preparations of rat liver L-type pyruvate kinase were found to contain about 3 mol of phosphate/mol of enzyme and were inactive as judged by a for P-enolpyruvate of 1.2 m M .In the course of studies on the phosphate content of these purified preparations, it was shown that cyclic AMP-dependent protein kinase catalyzed the dephosphorylation of phosphopyruvate kinase in the presence of MgADP.The equilibrium constant for this reverse reaction was 0.045.From this value, the free energy of hydrolysis