Properties of a Nucleoside Diphosphokinase from Liver Mitochondria and Its Relationship to the Adenosine Triphosphate-Adenosine Diphosphate Exchange Reaction

Abstract

A nucleoside diphosphokinase which also catalyzes an adenosine triphosphate-adenosine diphosphate exchange reaction has been extracted from bovine liver mitochondria and purified by conventional methods of protein fractionation. A comparison of the catalytic properties of the two activities indicates that both are catalyzed by the same enzyme, which is different in several respects from the nucleoside diphosphokinase previously isolated by others from rat liver and from erythrocytes. Evidence is presented that the enzyme herein described also catalyzes the dinitrophenol-sensitive ATP-ADP exchange reaction when bound to intact mitochondria and to phosphorylating submitochondrial particles.