Catalytic mechanism of P450 enzymes

Copyright information:

Taken from "Cytochromes P450: a success story"

Genome Biology 2000;1(6):reviews3003.1-reviews3003.9.

Published online 8 Dec 2000

PMCID:PMC138896.

Copyright © 2000 GenomeBiology.com

P450s are usually mono-oxygenases, catalyzing the insertion of one of the atoms of molecular oxygen into a substrate, the second atom of oxygen being reduced to water. The most frequently catalyzed reaction is hydroxylation (O insertion) using the very reactive and electrophilic iron-oxo intermediate (species [C], bottom row). The hydroperoxo form of the enzyme (species [B]) is also an electrophilic oxidant catalyzing OH insertion. Nucleophilic attack can be catalyzed by species [A] and [B] ; reduction, isomerization or dehydration are catalyzed by the oxygen-free forms of the enzyme. This, together with the variety of the apoproteins and intrinsic reactivity of all their substrates explains the extraordinary diversity of reactions catalyzed by P450 enzymes.