The Na+/e− stoichiometry of the Na+‐motive NADH : quinone oxidoreductase in Vibrio alginolyticus

FEBS Letters

Murtazina, Rachilya A¹  Bogachev, Alexander V¹  Skulachev, Vladimir P¹ 

[1] Department of Bioenergetics, A.N. Belozersky Institute of Physico–Chemical Biology, Moscow State University, Moscow 119899, Russia

关键词: Na+/e− stoichiometry;    Na+-motive NADH : quinone oxidoreductase;    Vibrio alginolyticus;    and;    transmembrane differences in H+ and Na+ electrochemical potentials;    respectively;    ΔΨ;    transmembrane difference in electric potentials;    CCCP;    m-chlorocarbonylcyanide phenylhydrazone;    HQNO;    2-heptyl-4-hydrooxyquinoline N-oxide;    TPP+;    tetraphenyl phosphonium;    TTFB;    4;    5;    6;    7-tetra-chloro-2-trifluoromethylbenzimidazole;   

DOI  :  10.1016/S0014-5793(97)00536-X

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

A method is proposed to estimate the stoichiometries of primary Na⁺-pumps in intact bacterial cells. It is based on technique when the H⁺/e⁻ stoichiometry is measured in the presence of protophorous uncoupler and in the absence of penetrating ions other than H⁺. Under these conditions, the H⁺ influx discharges membrane potential generated by the Na⁺ pump so the Na⁺/e⁻ and H⁺/e⁻ ratios become equal. Using this approach it is shown that the Na⁺/e⁻ ratio for the Na⁺-motive NADH : quinone oxidoreductase of Vibrio alginolyticus is equal to 0.71±0.06. The Na⁺/e⁻ stoichiometry appears to be ≈1, provided that the contribution of the non-coupled NADH : quinone oxidoreductase, which is resistant to low HQNO concentrations, is taken into account.

【 授权许可】

Unknown