OXIDATIVE PHOSPHORYLATION IN BACTERIA

I. OXIDATIVE PHOSPHORYLATION OF GRAM-POSITIVE AND GRAM-NEGATIVE BACTERIA

Abstract

Oxidative phosphorylation in particulate fractions of eleven bacteria was examined without adding any soluble factor. The bacteria examined which could oxidize both NADH and succinate were divided from their properties of phosphorylation into the following three groups; (i) phosphorylation is scarcely coupled to the oxidation of both substrates, (ii) the P:O ratio in NADH oxidation is nearly equal to that in succinate oxidation, and (iii) the P:O ratio in NADH oxidation is lower than that in succinate oxidation. The bacteria whose P:O ratio in NADH oxidation is higher than that in succinate oxidation were not observed.
In small particles of strains from group (ii) 0.1mM of cyanide inhibited NADH and succinate oxidation at a similar rate, while in small particles of strains from group (iii) cyanide inhibited succinate oxidation more strongly than NADH oxidation.
These groups agree well with the groups classified by the quinones present. The bacteria in group (ii) contain benzoquinones alone or, at least, mainly, and those in group (iii) contain naphthoquinones alone. From these observations, the role of quinones in oxidative phosphorylation of bacterial particles was discussed.