Reaction: nitric oxide + H2O + ferricytochrome c = nitrite + ferrocytochrome c + 2 H+
Glossary: nitric oxide = NO = nitrogen(II) oxide
Other name(s): cd-cytochrome nitrite reductase; [nitrite reductase (cytochrome)] [misleading, see comments.]; cytochrome c-551:O2, NO2+ oxidoreductase; cytochrome cd; cytochrome cd1; hydroxylamine (acceptor) reductase; methyl viologen-nitrite reductase; nitrite reductase (cytochrome; NO-forming)
Systematic name: nitric-oxide:ferricytochrome-c oxidoreductase
Comments: The reaction is catalysed by two types of enzymes, found in the perimplasm of denitrifying bacteria. One type comprises proteins containing multiple copper centres, the other a heme protein, cytochrome cd1. Acceptors include c-type cytochromes such as cytochrome c-550 or cytochrome c-551 from Paracoccus denitrificans or Pseudomonas aeruginosa, and small blue copper proteins such as azurin and pseudoazurin. Cytochrome cd1 also has oxidase and hydroxylamine reductase activities. May also catalyse the reaction of hydroxylamine reductase (EC 188.8.131.52) since this is a well-known activity of cytochrome cd1.
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, UM-BBD, CAS registry number: 9080-03-9
1. Miyata, M. and Mori, T. Studies on denitrification. X. The "denitrifying enzyme" as a nitrite reductase and the electron donating system for denitrification. J. Biochem. (Tokyo) 66 (1969) 463-471. [PMID: 5354021]
2. Chung, C.W. and Najjar, V.A. Cofactor requirements for enzymatic denitrification. I. Nitrite reductase. J. Biol. Chem. 218 (1956) 617-625.
3. Walker, G.C. and Nicholas, D.J.D. Nitrite reductase from Pseudomonas aeruginosa. Biochim. Biophys. Acta 49 (1961) 350-360.
4. Singh, J. Cytochrome oxidase from Pseudomonas aeruginosa. III. Reduction of hydroxylamine. Biochim. Biophys. Acta 333 (1974) 28-36.
5. Michalski, W.P. and Nicholas, D.J.D. Molecular characterization of a copper-containing nitrite reductase from Rhodopseudomonas sphaeriodes forma sp. Denitrificans. Biochim. Biophys. Acta 828 (1985) 130-137.
6. Godden, J.W., Turley, S., Teller, D.C., Adman, E.T., Liu, M.Y., Payne, W.J. and Legall, J. The 2.3 angstrom X-ray structure of nitrite reductase from Achromobacter cycloclastes. Science 253 (1991) 438-442. [PMID: 1862344]
7. Williams, P.A., Fulop, V., Leung, Y.C., Chan, C., Moir, J.W.B., Howlett, G., Ferguson, S.J., Radford, S.E. and Hajdu, J. Pseudospecific docking surfaces on electron transfer proteins as illustrated by pseudoazurin, cytochrome c-550 and cytochrome cd1 nitrite reductase. Nat. Struct. Biol. 2 (1995) 975-982. [PMID: 7583671]
8. Hole, U.H., Vollack, K.U., Zumft, W.G., Eisenmann, E., Siddiqui, R.A., Friedrich, B. and Kroneck, P.M.H. Characterization of the membranous denitrification enzymes nitrite reductase (cytochrome cd1) and copper-containing nitrous oxide reductase from Thiobacillus denitrificans. Arch. Microbiol. 165 (1996) 55-61. [PMID: 8639023]
9. Zumft, W.G. Cell biology and molecular basis of denitrification. Microbiol. Mol. Biol. Rev. 61 (1997) 533-616. [PMID: 9409151]
10. Ferguson, S.J. Nitrogen cycle enzymology. Curr. Opin. Chem. Biol. 2 (1998) 182-193. [PMID: 9667932]
11. Vijgenboom, E., Busch, J.E. and Canters, G.W. In vitro studies disprove the obligatory role of azurin in denitrification in Pseudomonas aeruginosa and show that azu expression is under the control of RpoS and ANR. Microbiology 143 (1997) 2853-2863. [PMID: 9308169]