Nitrification Mechanisms for the P460 Enzymes.

ABSTRACT: The oxidation of hydroxylamine was studied by quantum chemical modeling. Hydroxylamine is the product of ammonia oxidation in ammonia monooxygenase. That mechanism has been studied recently by quantum chemical modeling as here. Only two enzymes can oxidize hydroxylamine, hydroxylamine oxidase and cytochrome-P460. Both employ the unusual P460-heme cofactor. In hydroxylamine oxidase, there is a covalently linked tyrosine, while in cytochrome-P460, there is a covalently linked lysine. The calculations give explanations for the experimental findings that NO is the final product in hydroxylamine oxidase, while N₂O is the final product in cytochrome-P460. The effect of the covalent attachments has been investigated, and reasons for their presence have been given. The methodology used,

SUBMITTER: Siegbahn PEM 

PROVIDER: S-EPMC11726666 | biostudies-literature | 2025 Jan

REPOSITORIES: biostudies-literature