In animals, P450 enzymes serve two major functions: (1) biosynthesis of steroids, fatty acids, and bile acids; (2) metabolism of endogenous and a wide variety of exogenous substrates, such as toxins and drugs. The four major families involved in drug metabolism are CYP 1,2,3, and 4. CYP1A2 is an aryl hydrocarbon hydroxylase involved in the metabolism of endogenous compounds and xenobiotics. It is one of the major drug metabolising enzymes in humans.
