Mixed function oxidase

Mixed function oxidase is the name of a family of oxidase enzymes which each of the two atoms of oxygen in O2 is used for a different function in the reaction. Oxidase is a general name for enzymes that catalyze oxidations in which molecular oxygen is the electron acceptor but oxygen atoms do not appear in the oxidized product. Often oxygen is either reduced to water (cytochrome oxidase of the mitochondrial electron-transfer chain) or hydrogen peroxide (dehydrogenation of fatty acyl-CoA in peroxisomes). Most of the oxidases are flavoproteins.

The name "mixed-function oxidase" indicates that the enzyme oxidizes two different substrate simultaneously. Desaturation of fatty acyl-CoA in vertebrates is an example of the mixed-function oxidase reaction. In the process, saturated fatty acyl-CoA and NADPH are oxidized by molecular oxygen (O2) to produce monounsaturated fatty acyl-CoA, NADP+ and 2 moleculaes of water.

The mixed-function oxidase reaction proceedes as follows:

AH + BH2 + O2 --> AOH + B + H2O