Cytochrome P450 enzymes perform an assortment of modifications on a variety of ligands, utilizing its large active site and its ability to bind more than one substrate at a time to perform complicated chemical alterations in the metabolism of endogenous and exogenous compounds. These include hydroxylation, epoxidation of olefins, aromatic oxidation, heteroatom oxidations, N- and O- dealkylation reactions, aldehyde oxidations, dehydrogenation reactions, and aromatase activity. Hydroxylation of an sp3 C-H bond is one of the ways in which<unk>  (and cytochrome P450 oxygenases) affects its ligand. In fact, hydroxylation is sometimes followed by dehydrogenation, leading to more complex metabolites. An example of a molecule that undergoes more than one reaction due to<unk>  includes tamoxifen, which is hydroxylated to 4-hydroxy-tamoxifen and then dehydrated to 4-hydroxy-tamoxifen quinone methide. Two mechanisms have been proposed as the primary pathway of hydroxylation in P450 enzymes. Two of the most commonly proposed mechanisms used for the hydroxylation of an sp3 C–H bond. The first pathway suggested is a cage-controlled radical method ("oxygen rebound"), and the second involves a concerted mechanism that does not utilize a radical intermediate but instead acts very quickly via a "radical clock".
CYP3A4
CYP1A2
CYP2C19
CYP2D6
CYP3A5
CYP2C8
CYP2C9
CYP2J2