[Oxidative phosphorylation capacity of Rhodopseudomonas palustris during growth in light and darkness]

Assimilation of oxygen by the cells of Rhodopseudomonas palustris grown in the light and in the darkness is stimulated by p-chlorocarbonylcyanidephanylhydrazone, suggesting respiration coupled to phosphorylatin. Membranes of the cells grown in the light are capable of oxidative phosphorylation in the course of electron transport from NADH and succinate to O2 with P/O being 0.03 and 0.20, respectively. Membranes of the cells grown in the darkness in aerobic conditions are capable of oxidative phosphorylation in the presence of NADH, succinate and ascorbate + phenazinemetasulphate with P/O being 0.25, 0.40 and 0.06, respectively. Phosphorylation during oxidation of ascorbate + phenazinemetasulphate in the cells grown in the darkness suggests that the third point of coupling has appeared as a result of synthesis of cytochrome a. There are only minor differences in phosphorylation in the membranes of the cells grown in the light and in the darkness, as was shown by its susceptibility to p-chlorocarbonylcyanidephenyl-hydrazone, oligomycin, antimycin A and cyanide.