title: Membrane-bound respiratory of Spirillum itersonii.
abstract: The membrane-bound respiratory system of the gram-negative bacterium Spirillum itersonii was investigated. It contains cytochromes b (558), c (550), and o (558) and beta-dihydro-nicotinamide adenine dinucleotide (NADH) and succinate oxidase activities under all growth conditions. It is also capable of producing D-lactate and alpha-glycerophosphate dehydrogenases when grown with lactate or glycerol as sole carbon source. Membrane-bound malate dehydrogenase was not detectable under any conditions, although there is high activity of soluble nicotinamide adenine dinucleotide: malate dehydrogenase. When grown with oxygen as the sole terminal electron acceptor, approximately 60% of the total b-type cytochrome is present as cytochrome o, whereas only 40% is present as cytochrome o in cells grown with nitrate in the presence of oxygen. Both NADH and succinate oxidase are inhibited by azide, cyanide, antimycin A, and 2-n-heptyl-4-hydroxyquinoline-N-oxidase at low concentrations. The ability of these inhibitors to completely inhibit oxidase activity at low concentrations and their effects upon the aerobic steady-state reduction levels of b- and c-type cytochromes as well as the aerobic steady-state reduction levels obtained with NADH, succinate, and ascorbate-dichlorophenolindophenol suggest that presence of an unbranched respiratory chain in S. itersonii with the order ubiquinone leads to b leads to c leads to c leads to oxygen.
mesh_terms: D000968:Antimycin A / Q000494:pharmacology; D003580:Cytochromes / Q000378:metabolism*; D004579:Electron Transport; D005993:Glycerolphosphate Dehydrogenase / Q000378:metabolism; D006912:Hydroxyquinolines / Q000494:pharmacology; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D009243:NAD / Q000378:metabolism; D013139:Spirillum / Q000201:enzymology*; D013385:Succinate Dehydrogenase / Q000378:metabolism; D014451:Ubiquinone / Q000378:metabolism*
chemical_list: D003580:Cytochromes; D006912:Hydroxyquinolines; D009243:NAD; D014451:Ubiquinone; D000968:Antimycin A; D005993:Glycerolphosphate Dehydrogenase; D007770:L-Lactate Dehydrogenase; D013385:Succinate Dehydrogenase