Hydroxylamine dehydrogenase explained

Hydroxylamine dehydrogenase
Ec Number:	1.7.2.6
Cas Number:	9075-43-8

Hydroxylamine dehydrogenase (HAO (ambiguous)) is an enzyme with systematic name hydroxylamine:ferricytochrome-c oxidoreductase.^{[1] [2] [3] [4] [5]} This enzyme catalyses the following chemical reaction

(1) hydroxylamine + H₂O + 2 ferricytochrome c

\rightleftharpoons nitrite + 2 ferrocytochrome c + 5 H⁺

(2) hydroxylamine + ferricytochrome c

\rightleftharpoons nitric oxide + ferrocytochrome c + 3 H⁺

The enzymes from the nitrifying bacterium Nitrosomonas europaea and the methylotrophic bacterium Methylococcus capsulatus are hemoproteins.

Notes and References

1. Rees MK . Studies of the hydroxylamine metabolism of Nitrosomonas europaea. I. Purification of hydroxylamine oxidase . Biochemistry . 7 . 1 . 353–66 . January 1968 . 5758552 . 10.1021/bi00841a045 .
2. Hooper AB, Terry KR . Hydroxylamine oxidoreductase of Nitrosomonas. Production of nitric oxide from hydroxylamine . Biochimica et Biophysica Acta . 571 . 1 . 12–20 . November 1979 . 497235 . 10.1016/0005-2744(79)90220-1 .
3. Hooper AB, Balny C . Reaction of oxygen with hydroxylamine oxidoreductase of Nitrosomonas: fast kinetics . FEBS Letters . 144 . 2 . 299–303 . August 1982 . 7117545 . 10.1016/0014-5793(82)80658-3 . 9726167 . free .
4. Lipscomb JD, Hooper AB . Resolution of multiple heme centers of hydroxylamine oxidoreductase from Nitrosomonas. 1. Electron paramagnetic resonance spectroscopy . Biochemistry . 21 . 17 . 3965–72 . August 1982 . 6289867 . 10.1021/bi00260a010 .
5. Poret-Peterson AT, Graham JE, Gulledge J, Klotz MG . Transcription of nitrification genes by the methane-oxidizing bacterium, Methylococcus capsulatus strain Bath . The ISME Journal . 2 . 12 . 1213–20 . December 2008 . 18650926 . 10.1038/ismej.2008.71 . free .