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The Na + /e − stoichiometry of the Na + ‐motive NADH : quinone oxidoreductase in Vibrio alginolyticus
Author(s) -
Bogachev Alexander V,
Murtazina Rachilya A,
Skulachev Vladimir P
Publication year - 1997
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(97)00536-x
Subject(s) - stoichiometry , vibrio alginolyticus , chemistry , oxidoreductase , quinone , membrane , vibrio , stereochemistry , enzyme , biochemistry , bacteria , biology , organic chemistry , genetics
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.