| EC |
1.7.2.6 |
| Accepted name: |
hydroxylamine dehydrogenase |
| Reaction: |
hydroxylamine + H2O + 4 ferricytochrome c = nitrite + 4 ferrocytochrome c + 5 H+ |
| Other name(s): |
HAO (ambiguous); hydroxylamine oxidoreductase (ambiguous); hydroxylamine oxidase (misleading) |
| Systematic name: |
hydroxylamine:ferricytochrome-c oxidoreductase (nitrite-forming) |
| Comments: |
The enzymes from the nitrifying bacterium Nitrosomonas europaea [1,4] and the methylotrophic bacterium Methylococcus capsulatus [5] are hemoproteins with seven c-type hemes and one specialized P-460-type heme per subunit. The enzyme converts hydroxylamine to nitrite via an enzyme-bound nitroxyl intermediate [3]. While nitrite is the main product, the enzyme from Nitrosomonas europaea can also produce nitric oxide by catalysing the activity of EC 1.7.2.9, hydroxylamine oxidase [2]. |
| Links to other databases: |
BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 9075-43-8 |
| References: |
| 1. |
Rees, M. Studies of the hydroxylamine metabolism of Nitrosomonas europaea. I. Purification of hydroxylamine oxidase. Biochemistry 7 (1968) 353–366. [PMID: 5758552] |
| 2. |
Hooper, A.B. and Terry, K.R. Hydroxylamine oxidoreductase of Nitrosomonas. Production of nitric oxide from hydroxylamine. Biochim. Biophys. Acta 571 (1979) 12–20. [DOI] [PMID: 497235] |
| 3. |
Hooper, A.B. and Balny, C. Reaction of oxygen with hydroxylamine oxidoreductase of Nitrosomonas: fast kinetics. FEBS Lett. 144 (1982) 299–303. [DOI] [PMID: 7117545] |
| 4. |
Lipscomb, J.D. and Hooper, A.B. Resolution of multiple heme centers of hydroxylamine oxidoreductase from Nitrosomonas. 1. Electron paramagnetic resonance spectroscopy. Biochemistry 21 (1982) 3965–3972. [PMID: 6289867] |
| 5. |
Poret-Peterson, A.T., Graham, J.E., Gulledge, J. and Klotz, M.G. Transcription of nitrification genes by the methane-oxidizing bacterium, Methylococcus capsulatus strain Bath. ISME J. 2 (2008) 1213–1220. [DOI] [PMID: 18650926] |
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| [EC 1.7.2.6 created 1972 as EC 1.7.3.4, part transferred 2012 to EC 1.7.2.6, modifed 2021, modified 2021] |
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