title: Cytochrome bd oxidase from Escherichia coli displays high catalase activity: an additional defense against oxidative stress.
abstract: Cytochrome bd oxygen reductase from Escherichia coli has three hemes, b558, b595 and d. We found that the enzyme, as-prepared or in turnover with O2, rapidly decomposes H2O2 with formation of approximately half a mole of O2 per mole of H2O2. Such catalase activity vanishes upon cytochrome bd reduction, does not compete with the oxygen-reductase activity, is insensitive to NO, CO, antimycin-A and N-ethylmaleimide (NEM), but is inhibited by cyanide (Ki ~2.5μM) and azide. The activity, possibly associated with heme-b595, was also observed in catalase-deficient E. coli cells following cytochrome bd over-expression suggesting a protective role against oxidative stress in vivo.
authors.affiliation: Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory, Moscow 119991, Russian Federation.
authors.forename: Vitaliy B
authors.initials: VB
authors.lastname: Borisov
authors.forename: Elena
authors.initials: E
authors.lastname: Forte
authors.forename: Albert
authors.initials: A
authors.lastname: Davletshin
authors.forename: Daniela
authors.initials: D
authors.lastname: Mastronicola
authors.forename: Paolo
authors.initials: P
authors.lastname: Sarti
authors.forename: Alessandro
authors.initials: A
authors.lastname: Giuffrè
mesh_terms: D000818:Animals; D002374:Catalase / Q000737:chemistry*; D002417:Cattle; D003573:Cytochrome b Group; D003580:Cytochromes / Q000037:antagonists & inhibitors / Q000737:chemistry*; D004229:Dithiothreitol / Q000737:chemistry; D045222:Electron Transport Chain Complex Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry*; D004791:Enzyme Inhibitors / Q000737:chemistry; D004926:Escherichia coli / Q000201:enzymology*; D029968:Escherichia coli Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000737:chemistry; D006873:Hydroquinones / Q000737:chemistry; D007700:Kinetics; D009243:NAD / Q000737:chemistry; D016660:NAD(P)H Dehydrogenase (Quinone) / Q000737:chemistry; D016877:Oxidants / Q000737:chemistry; D018384:Oxidative Stress; D010088:Oxidoreductases / Q000037:antagonists & inhibitors / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry; D051381:Rats; D019163:Reducing Agents / Q000737:chemistry; D012966:Sodium Cyanide / Q000737:chemistry
chemical_list: D003573:Cytochrome b Group; D003580:Cytochromes; D045222:Electron Transport Chain Complex Proteins; D004791:Enzyme Inhibitors; D029968:Escherichia coli Proteins; D006873:Hydroquinones; D016877:Oxidants; D019163:Reducing Agents; D009243:NAD; D006861:Hydrogen Peroxide; D010088:Oxidoreductases; D002374:Catalase; D016660:NAD(P)H Dehydrogenase (Quinone); C040077:cytochrome bd terminal oxidase complex, E coli; D012966:Sodium Cyanide; D010100:Oxygen; D004229:Dithiothreitol