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Energy-linked reactions in photosynthetic bacteria

1967; Elsevier BV; Volume: 121; Issue: 2 Linguagem: Inglês

10.1016/0003-9861(67)90095-1

1096-0384

Donald L. Keister, Norma Jean Yike,

Porphyrin and Phthalocyanine Chemistry

Succinate-linked NAD+ reduction by Rhodospirillum rubrum chromatophores has been demonstrated to be driven by ATP and pyrophosphate as well as light. Gramicidin, m-chlorocarbonylcyanide phenylhydrazone, desaspidin, dicumarol, and quiuacrine are well known uncouplers which inhibited both the light and ATP-driven reactions. The electron transport inhibitors, 2-heptyl-4-hydroxyquinolme-N-oxide, antimycin A, and a 3-alkyl hydroxy naphthoquinone, inhibited the light-driven reduction but had no effect on the ATP-driven reaction. Roteunone and amytal inhibited both reactions. The effect of these compounds on NAD+ reduction has been compared with their effect on photophosphorylation and on the energy-linked transhydrogenase. The light-driven NAD+ reduction was stimulated by, but did not require, divalent cations, bovine serum albumin, and oligomycin. The energy-linked NAD+ reduction is proposed to occur by reversed electron flow in the oxidative electron transport chain.