delta pH driven energy-linked NAD+ reduction in Rhodospirillum rubrum chromatophores.
An artificial proton gradient provided sufficient energy to drive reverse electron transport from succinate to NADH:ubiquinone oxidoreductase in chromatophores isolated from Rhodospirillum rubrum. The pH gradient created was able to reduce NAD+. In chromatophores, the optimal rate of NAD+ reduction was about 0.4-0.45 mumol NADH formed/min.mumol bacteriochlorophyll at delta pH 3. The presence of oligomycin was an obligate factor in the assay in order to observe the maximal rate of NAD+ reduction. The rate of NADH formation was dependent on the size of the induced pH gradient. The total NADH formed had a threshold value for the imposed delta pH. The effect of different inhibitors and uncouplers was demonstrated. Comparison between ATP, PPi, and light with the pH jump driven NAD+ reduction rate was studied.
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B F
BF
Department of Biochemistry, Arrhenius Laboratory, University of Stockholm, Sweden.
D000255:Adenosine Triphosphate / Q000378:metabolism; D020130:Bacterial Chromatophores / Q000187:drug effects / Q000378:metabolism*; D004579:Electron Transport; D004734:Energy Metabolism; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009243:NAD / Q000378:metabolism*; D010084:Oxidation-Reduction; D012247:Rhodospirillum rubrum / Q000378:metabolism*; D014475:Uncoupling Agents / Q000494:pharmacology
D014475:Uncoupling Agents; D009243:NAD; D000255:Adenosine Triphosphate