title: H(2)O(2)-forming NADH oxidase with diaphorase (cytochrome) activity from Archaeoglobus fulgidus.
abstract: An enzyme exhibiting NADH oxidase (diaphorase) activity was isolated from the hyperthermophilic sulfate-reducing anaerobe Archaeoglobus fulgidus. N-terminal sequence of the protein indicates that it is coded for by open reading frame AF0395 in the A. fulgidus genome. The gene AF0395 was cloned and its product was purified from Escherichia coli. Like the native NADH oxidase (NoxA2), the recombinant NoxA2 (rNoxA2) has an apparent molecular mass of 47 kDa, requires flavin adenine dinucleotide for activity, has NADH-specific activity, and is thermostable. Hydrogen peroxide is the product of bivalent oxygen reduction by rNoxA2 with NADH. The rNoxA2 is an oxidase with diaphorase activity in the presence of electron acceptors such as tetrazolium and cytochrome c. During purification NoxA2 remains associated with the enzyme responsible for D-lactate oxidation, the D-lactate dehydrogenase (Dld), and the genes encoding NoxA2 and Dld are in the same transcription unit. Together these results suggest that NADH oxidase may be involved in electron transfer reactions resulting in sulfate respiration.
authors.affiliation: Department of Microbiology, Molecular Biology and Biochemistry, University of Idaho, Moscow, Idaho 83844-3052, USA.
authors.forename: D W
authors.initials: DW
authors.lastname: Reed
authors.forename: J
authors.initials: J
authors.lastname: Millstein
authors.forename: P L
authors.initials: PL
authors.lastname: Hartzell
mesh_terms: D000595:Amino Acid Sequence; D019843:Archaeal Proteins / Q000302:isolation & purification / Q000378:metabolism; D019611:Archaeoglobus fulgidus / Q000201:enzymology*; D004795:Enzyme Stability; D005182:Flavin-Adenine Dinucleotide / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism*; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000302:isolation & purification / Q000378:metabolism*; D009245:NADH Dehydrogenase / Q000302:isolation & purification / Q000378:metabolism*; D009247:NADH, NADPH Oxidoreductases / Q000302:isolation & purification / Q000378:metabolism*; D010084:Oxidation-Reduction; D011485:Protein Binding; D020539:Sequence Analysis, Protein
chemical_list: D019843:Archaeal Proteins; D009097:Multienzyme Complexes; D005182:Flavin-Adenine Dinucleotide; D006861:Hydrogen Peroxide; D007770:L-Lactate Dehydrogenase; C023107:NADH oxidase; D009247:NADH, NADPH Oxidoreductases; D009245:NADH Dehydrogenase