title: A spectrophotometric assay for dissimilatory nitrite reductases.
abstract: A spectrophotometric assay for dissimilatory nitrite reductases has been developed utilizing mammalian cytochrome c (equine heart) as reductant and spectrophotometric agent. The copper-containing nitrite reductase from Achromobacter cycloclastes has been shown to have apparent Km's for reduced cytochrome c and nitrite of 86 +/- 5 and 5.63 +/- 0.03 microM, respectively. The heme cd-containing enzyme from Pseudomonas stutzeri was shown to have apparent Km's for reduced cytochrome c and nitrite of 260 +/- 60 and 1.8 +/- 0.8 microM, respectively. This assay represents a simple, general method for consistently evaluating the activity of the copper- and heme cd-containing nitrite reductases that are capable of utilizing readily available mammalian cytochrome c as electron donor and should be useful for mechanistic studies of these enzymes.
authors.affiliation: Department of Chemistry, University of Virginia, Charlottesville 22901.
authors.forename: C L
authors.initials: CL
authors.lastname: Hulse
authors.forename: J M
authors.initials: JM
authors.lastname: Tiedje
authors.forename: B A
authors.initials: BA
authors.lastname: Averill
mesh_terms: D000421:Alcaligenes / Q000201:enzymology; D000818:Animals; D002849:Chromatography, Gas; D003300:Copper / Q000032:analysis; D003574:Cytochrome c Group / Q000032:analysis; D004583:Electrons; D006418:Heme / Q000032:analysis; D006736:Horses; D009206:Myocardium / Q000201:enzymology; D009247:NADH, NADPH Oxidoreductases / Q000032:analysis*; D009572:Nitrite Reductases / Q000032:analysis*; D010084:Oxidation-Reduction; D011549:Pseudomonas / Q000201:enzymology; D013053:Spectrophotometry / Q000379:methods
chemical_list: D003574:Cytochrome c Group; D006418:Heme; D003300:Copper; D009247:NADH, NADPH Oxidoreductases; D009572:Nitrite Reductases