Ammonia monooxygenase

Ammonia monooxygenase
Identifiers
EC no.1.14.99.39
Databases
IntEnzIntEnz view
BRENDABRENDA entry
ExPASyNiceZyme view
KEGGKEGG entry
MetaCycmetabolic pathway
PRIAMprofile
PDB structuresRCSB PDB PDBe PDBsum
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PMCarticles
PubMedarticles
NCBIproteins

Ammonia monooxygenase (EC 1.14.99.39, AMO) is an enzyme, which catalyses the following chemical reaction

ammonia + AH2 + O2 NH2OH + A + H2O

Ammonia monooxygenase contains copper and possibly nonheme iron. AMO is the first enzyme in ammonia oxidation. Aerobic oxidation of ammonia to hydroxylamine via AMO is an endergonic reaction. So, all aerobic ammonia oxidizing organisms conserve energy by further oxidizing hydroxylamine. It was believed that aerobic ammonia-oxidizing bacteria oxidize hydroxylamine to nitrite using octahaem hydroxylamine oxidoreductase (HAO). Recently, it was shown that the product of HAO is not nitrite but nitric oxide, which is further oxidized to nitrite by an unknown enzyme.