Partial Resolution of the Enzymes Catalyzing Oxidative Phosphorylation

Abstract 1. Treatment with cholate in the presence of salt resolves submitochondrial particles from bovine heart into two fractions: heavy particles, which contain cytochrome oxidase and other members of the respiratory chain except cytochrome c but are devoid of energy coupling, and light particles (E-particles) which contain no cytochrome oxidase but catalyze 32Pi-ATP exchange. The 32Pi-ATP exchange in E-particles is abolished by rutamycin and uncouplers or by the combined action of valinomycin, nigericin, and potassium ions. 2. E-particles contain cytochrome b and cytochrome c1 and catalyze succinate and NADH-dehydrogenase activities. Rates of other electron transport activities are less than 10% of those of the parent particles. The content of phospholipid is 3 times that of the parent particles. 3. Reconstitution of E-particles with purified cytochrome oxidase results in the restoration of succinate-cytochrome c reductase and NADH-cytochrome c reductase activities, and in ATP formation associated with the oxidation of NADH or succinate.