title: A novel aerobic respiratory chain-linked NADH oxidase system in Zymomonas mobilis.
abstract: Membrane vesicles prepared from Zymomonas mobilis oxidized NADH exclusively, whereas deamino-NADH was little oxidized. In addition, the respiratory chain-linked NADH oxidase system exhibited only a single apparent Km value of approximately 66 microM for NADH. The NADH oxidase was highly sensitive to the respiratory chain inhibitor 2-heptyl-4-hydroxyquinoline-N-oxide. However, the NADH:quinone oxidoreductase was not sensitive to 2-heptyl-4-hydroxyquinoline-N-oxide and was highly resistant to another respiratory chain inhibitor, rotenone. Electron transfer from NADH to oxygen generated a proton electrochemical gradient (inside positive) in inside-out membrane vesicles. In contrast, electron transfer from NADH to ubiquinone-1 generated no electrochemical gradient. These findings indicate that Z. mobilis possesses only NADH:quinone oxidoreductase lacking the energy coupling site.
authors.affiliation: Department of Microbiology, Changwon National University, Kyungnam, Republic of Korea.
authors.forename: Y J
authors.initials: YJ
authors.lastname: Kim
authors.forename: K B
authors.initials: KB
authors.lastname: Song
authors.forename: S K
authors.initials: SK
authors.lastname: Rhee
mesh_terms: D000332:Aerobiosis; D004734:Energy Metabolism / Q000502:physiology; D006912:Hydroxyquinolines / Q000494:pharmacology; D008564:Membrane Potentials / Q000502:physiology; D008566:Membranes / Q000201:enzymology; D009097:Multienzyme Complexes / Q000037:antagonists & inhibitors / Q000378:metabolism*; D016660:NAD(P)H Dehydrogenase (Quinone) / Q000378:metabolism; D009247:NADH, NADPH Oxidoreductases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology*; D011522:Protons; D014451:Ubiquinone / Q000378:metabolism; D017355:Zymomonas / Q000201:enzymology*
chemical_list: D006912:Hydroxyquinolines; D009097:Multienzyme Complexes; D011522:Protons; D014451:Ubiquinone; C001333:2-(n-heptyl)-4-hydroxyquinoline N-oxide; C023107:NADH oxidase; D009247:NADH, NADPH Oxidoreductases; D016660:NAD(P)H Dehydrogenase (Quinone)