INTERMEDIATE REACTIONS IN THE PHOSPHORYLATION COUPLED TO THE OXIDATION OF REDUCED CYTOCHROME C

Abstract
A cytochrome oxidase-containing particle which catalyzes only the phosphorylation step coupled to the oxidation of reduced cytochrome c has been prepared from beef heart mitochondria. Oxidative phosphorylation by this particle exhibits an absolute requirement for the reduced cytochrome c coupling factor. During the oxidation of cytochrome c by this particle in the presence of the specific coupling factor and magnesium ions, a soluble, nonphosphorylated substance is formed which readily reacts with ADP and Pi to form ATP. The substance is formed only if cytochrome c is oxidized in the presence of the coupling factor, and the formation is prevented by dinitrophenol. The activated substance can be purified by chromatography or by starch gel electrophoresis.