Oxidative phosphorylation by subcellular particles from yeast

Abstract

Washed particulate fractions obtained by differential centrifugings from the baker''s yeast disintegrated by high-speed reciprocal shaking with glass beads show phosphorylation coupled to the oxidation of succinate and lactate. Phosphorylation is dependent on the presence of an adenosine triphosphate-trapping system, yields glucose 6-phosphate as the major product and is completely uncoupled by 2:4-dinitrophenol. Adenosine diphosphate is the only substance tested capable of acting as a phosphate acceptor; the other nucleoside diphosphates and adenosine monophosphate are completely inactive. The P/O values observed during succinate oxidation generally range from 0-6 to 0-9 and phosphorylation is not obligatorily coupled to respiration. Succinate is oxidized mainly or entirely to fumarate and malate. The oxidation of substrates other than succinate or lactate is dependent upon the nature of the disintegration procedure and subsequent isolation procedure.