title: Spectroscopic evidence for a copper-nitrosyl intermediate in nitrite reduction by blue copper-containing nitrite reductase.
abstract: The reactions of nitrogen monoxide (NO) with the blue copper-containing nitrite reductases from Alcaligenes sp. NCIB 11015 and Achromobacter cycloclastes IAM 1013 were investigated spectroscopically. The electron paramagnetic resonance (EPR) signals of the blue coppers vanished in the presence of NO at 77 K, being fully restored by the removal of NO. The additions of NO to the enzyme solutions resulted in the substantial bleaching of the visible absorption bands at room temperature. The reactions were also completely reversible. These results suggest the formation of a cuprous nitrosyl complex (Cu+-NO+), which is likely the intermediate in the enzymatic nitrite reduction.
authors.affiliation: Institute of Chemistry, College of General Education, Osaka University, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Suzuki
authors.forename: T
authors.initials: T
authors.lastname: Yoshimura
authors.forename: T
authors.initials: T
authors.lastname: Kohzuma
authors.forename: S
authors.initials: S
authors.lastname: Shidara
authors.forename: M
authors.initials: M
authors.lastname: Masuko
authors.forename: T
authors.initials: T
authors.lastname: Sakurai
authors.forename: H
authors.initials: H
authors.lastname: Iwasaki
mesh_terms: D000421:Alcaligenes / Q000201:enzymology; D003300:Copper / Q000032:analysis / Q000378:metabolism; D004578:Electron Spin Resonance Spectroscopy; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism*; D009572:Nitrite Reductases / Q000378:metabolism*; D009573:Nitrites / Q000378:metabolism*; D009609:Nitrous Oxide / Q000378:metabolism*; D011485:Protein Binding; D013053:Spectrophotometry
chemical_list: D009573:Nitrites; D003300:Copper; D009247:NADH, NADPH Oxidoreductases; D009572:Nitrite Reductases; D009609:Nitrous Oxide