A transmembrane electrical potential generated by respiration is not equivalent to a diffusion potential of the same magnitude for ATP synthesis by Bacillus firmus RAB.

摘要: Abstract ATP synthesis by starved whole cells of alkalophilic Bacillus firmus RAB was energized addition DL-malate or imposition a valinomycin-mediated K+ diffusion potential. At pH 9.0, the transmembrane electrical potentials produced these two means were similar in magnitude, at close to -170 mV. While N,N'-dicyclohexylcarbodiimide-sensitive occurred upon DL-malate, no synthesized response In contrast, Na+-dependent accumulation alpha-aminoisobutyric acid equally well potential 9.0. Even 7.0, more efficacious than energizing as assessed determining phosphorylation generated values different magnitudes. Both modes energization did, however, result 7.0. The results studies are consistent with model energy coupling which one pathway protons between respiratory proton pumps and H+-translocating ATPase is direct localized. Whereas an artificially imposed electrochemical gradient can energize under certain experimental conditions, proton-poor milieu that optimal for growth bacilli, may be crucial.