Hydroxylamine oxidase system

It seems very difficult to reconstitute the hydroxylamine oxidase system by mixing purified components, because the optimal pHs of hydroxylamine oxidore-ductase and cytochrome c oxidase are 9.6 and 5.6, respectively. However, as the optimal pH of the oxidoreductase is lowered to around 7 in the presence of ubiquinone-8 and oleic acid, the reconstitution of the system seems possible (Numata, 1989). When hydroxylamine and the oxidoreductase are added to the mixture of cytochromes c-554 and c-552 supplemented with ubiquinone-8 and oleic acid, cytochrome c-552 is reduced at pH 7.0, and ferrocytochrome c-552 thus formed is oxidized on addition of cytochrome c oxidase. Although these reactions are spectrally observed, the formation of nitrite is not observed, unfortunately, in the above system. 

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