Studies on the biosynthesis of cholesterol: XIII. phosphomevalonic kinase from liver

Abstract

The enzyme, phosphomevalonic kinase, which catalyzes the formation of 5-pyrophosphomevalonate from 5-phosphomevalonate and ATP has been purified from pig liver. The reaction is reversible, the position of equilibrium lying on the side of the forward reaction, and goes at optimum rate at pH 7.3 in the presence of 5 mM Mg++, 3.6 mM ATP, and 1 mM 5-phosphomevalonate. The effect of various metal ions and inhibitors on the enzyme is described. The Km for the enzyme is 0.3 mM. The preparation and some of the properties of 5-pyrophosphomevalonic acid are described.