Non Cyclic Electron Transport and Photophosphorylation in Rhodospirillum Rubrum Chromatohores

Abstract

The light-induced reduction of NAD⁺ by various electron donors in R.rubrum chromatophores was shown to be inhibited by the addition of ADP⁺Pi or uncouplers (FRENKEL 1958, ASH et al. 1961, Horio et al. 1963, VERNON 1963, KEISTER & YIKE 1967, GROMET-ELHANAN 1969). KEISTER &YIKE (1967) reported that in the light-induced succinate-linked NAD⁺ reduction oligomyc in released the inhibition by the phosphorylating reagents and that in the dark ATP could induce NAD⁺ reduction, although at a rate of only 10% to 20% of the rate in the light. These results led them to adopt the earlier suggestion by BOSE & GEST (1962) that NAD⁺ is reduced in the chromatophores via an energy-linked reverse electron transport.