KEGG   ENZYME: 1.7.2.6Help
Entry
EC 1.7.2.6                  Enzyme                                 

Name
hydroxylamine dehydrogenase;
HAO (ambiguous);
hydroxylamine oxidoreductase (ambiguous);
hydroxylamine oxidase (misleading)
Class
Oxidoreductases;
Acting on other nitrogenous compounds as donors;
With a cytochrome as acceptor
BRITE hierarchy
Sysname
hydroxylamine:ferricytochrome-c oxidoreductase
Reaction(IUBMB)
(1) hydroxylamine + H2O + 2 ferricytochrome c = nitrite + 2 ferrocytochrome c + 5 H+ [RN:R10164];
(2) hydroxylamine + ferricytochrome c = nitric oxide + ferrocytochrome c + 3 H+ [RN:R10165]
Reaction(KEGG)
Substrate
hydroxylamine [CPD:C00192];
H2O [CPD:C00001];
ferricytochrome c [CPD:C00125]
Product
nitrite [CPD:C00088];
ferrocytochrome c [CPD:C00126];
H+ [CPD:C00080];
nitric oxide [CPD:C00533]
Comment
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 produce nitric oxide as well [2].
History
EC 1.7.2.6 created 1972 as EC 1.7.3.4, part transferred 2012 to EC 1.7.2.6
Pathway
Nitrogen metabolism
Microbial metabolism in diverse environments
Orthology
K10535  
hydroxylamine dehydrogenase
Genes
MCA: 
MAH: 
NOC: 
NHL: 
NWA: 
NEU: 
NE0962(hao2) NE2044(hao1) NE2339(hao3)
NET: 
NIT: 
NII: 
NMU: 
MSC: 
SIL: 
MIN: 
Minf_2434(cccA)
MOX: 
 » show all
Taxonomy
Reference
1  [PMID:5758552]
  Authors
Rees MK.
  Title
Studies of the hydroxylamine metabolism of Nitrosomonas europaea. I. Purification of hydroxylamine oxidase.
  Journal
Biochemistry. 7 (1968) 353-66.
Reference
2  [PMID:497235]
  Authors
Hooper AB, Terry KR
  Title
Hydroxylamine oxidoreductase of Nitrosomonas. Production of nitric oxide from hydroxylamine.
  Journal
Biochim. Biophys. Acta. 571 (1979) 12-20.
Reference
3  [PMID:7117545]
  Authors
Hooper AB, Balny C.
  Title
Reaction of oxygen with hydroxylamine oxidoreductase of Nitrosomonas: fast kinetics.
  Journal
FEBS. Lett. 144 (1982) 299-303.
Reference
4  [PMID:6289867]
  Authors
Lipscomb JD, Hooper AB.
  Title
Resolution of multiple heme centers of hydroxylamine oxidoreductase from Nitrosomonas. 1. Electron paramagnetic resonance spectroscopy.
  Journal
Biochemistry. 21 (1982) 3965-72.
Reference
5  [PMID:18650926]
  Authors
Poret-Peterson AT, Graham JE, Gulledge J, Klotz MG
  Title
Transcription of nitrification genes by the methane-oxidizing bacterium, Methylococcus capsulatus strain Bath.
  Journal
ISME. J. 2 (2008) 1213-20.
Other DBs
ExplorEnz - The Enzyme Database: 
IUBMB Enzyme Nomenclature: 
ExPASy - ENZYME nomenclature database: 
BRENDA, the Enzyme Database: 
CAS: 
9075-43-8

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