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The Na + ‐translocating NADH: ubiquinone oxidoreductase from the marine bacterium Vibrio alginolyticus contains FAD but not FMN
Author(s) -
Pfenninger-Li Xiao Dan,
Dimroth Peter
Publication year - 1995
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 - 10.1016/0014-5793(95)00745-u
Subject(s) - oxidoreductase , menadione , flavoprotein , flavin group , flavin adenine dinucleotide , enzyme , biochemistry , chemistry , cofactor , flavin mononucleotide , nadh dehydrogenase , nad+ kinase , gene , protein subunit
The Na + ‐translocating NADH: ubiquinone oxidoreductase from Vibrio alginolyticus was extracted from the bacterial membranes and purified by ion exchange chromatographic procedures. The enzyme catalyzed NADH oxidation by suitable electron acceptors, e.g. menadione, and the Na + and NADH‐dependent reduction of ubiquinone‐1. Four dominant bands and a number of minor bands were visible on SDS‐PAGE that could be part of the enzyme complex. Flavin analyses indicated the presence of FAD but no FMN in the purified enzyme. FAD but no FMN were also present in V. alginolyticus membranes. FAD is therefore a prosthetic group of the Na + ‐translocating NADH:ubiquinone oxidoreductase and FMN is not present in the enzyme. The FAD was copurified with the NADH dehydrogenase. The purified enzyme exhibited an absorption spectrum with a maximum at 450 nm that is typical for a flavoprotein. Upon incubation with NADH this absorption disappeared indicating reduction of the enzyme‐bound FAD.