title: Enzymatic and energetic properties of the aerobic respiratory chain-linked NADH oxidase system in the marine bacterium Pseudomonas nautica.
abstract: Membranes of Pseudomonas nautica, grown aerobically on a complex medium, oxidized both NADH and deamino-NADH as substrates. The activity of membrane-bound NADH oxidase was activated by monovalent cations including Na+, Li+, and K+. The activation by Na+ was higher than that by Li+ and K+. The maximum activity of NADH oxidase was obtained at about pH 9.0 in the presence of 0.08 M NaCl. The NADH oxidase activity was completely inhibited by 60 microM 2-heptyl-4-hydroxyquinoline-N-oxide (HQNO), while the NADH:quinone oxidoreductase activity was about 37% inhibited by 60 microM HQNO. The activities of NADH oxidase and NADH:quinone oxidoreductase were about 40% inhibited by 60 microM rotenone. The fluorescence quenching technique revealed that electron transfer from NADH to ubiquinone-1 (Q-1) or oxygen generated a membrane potential (deltapsi) which was larger and more stable in the presence of Na+ than in the absence of Na+. However, the All was highly sensitive to a protonophore, carbonyl-cyanide m-chlorophenylhydrazone (CCCP) even at alkaline pH.
authors.affiliation: Department of Microbiology, College of Natural Sciences, Changwon National University, Korea.
authors.forename: K H
authors.initials: KH
authors.lastname: Cho
authors.forename: Y J
authors.initials: YJ
authors.lastname: Kim
mesh_terms: D001426:Bacterial Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry; D004579:Electron Transport; D006863:Hydrogen-Ion Concentration; D006912:Hydroxyquinolines / Q000494:pharmacology; D008564:Membrane Potentials; D008565:Membrane Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry; D009097:Multienzyme Complexes / Q000037:antagonists & inhibitors / Q000737:chemistry*; D009243:NAD / Q000031:analogs & derivatives* / Q000378:metabolism; D009247:NADH, NADPH Oxidoreductases / Q000037:antagonists & inhibitors / Q000737:chemistry*; D010100:Oxygen / Q000378:metabolism; D011190:Potassium Cyanide / Q000494:pharmacology; D011549:Pseudomonas / Q000201:enzymology*; D011808:Quinone Reductases / Q000037:antagonists & inhibitors; D012402:Rotenone / Q000494:pharmacology; D012492:Salts / Q000737:chemistry; D014451:Ubiquinone / Q000378:metabolism; D014475:Uncoupling Agents / Q000494:pharmacology
chemical_list: D001426:Bacterial Proteins; D006912:Hydroxyquinolines; D008565:Membrane Proteins; D009097:Multienzyme Complexes; D012492:Salts; D014475:Uncoupling Agents; D012402:Rotenone; D009243:NAD; D014451:Ubiquinone; C001333:2-(n-heptyl)-4-hydroxyquinoline N-oxide; C032140:nicotinamide-hypoxanthine dinucleotide; C023107:NADH oxidase; D009247:NADH, NADPH Oxidoreductases; C041831:NADH dehydrogenase (quinone); D011808:Quinone Reductases; C025203:Ubiquinone Q1; D011190:Potassium Cyanide; D010100:Oxygen