Members of CYP2J are expressed in multiple tissues in mice and humans. They function as catalysts of arachidonic acid metabolism and are active in the metabolism of fatty acids to generate bioactive compounds. Human CYP2J2, also called arachidonic acid epoxygenase or albendazole monooxygenase (hydroxylating), is a membrane-bound cytochrome P450 primarily expressed in the heart and plays a significant role in cardiovascular diseases. The CYP2J subfamily belongs to the large cytochrome P450 (P450, CYP) superfamily of heme-containing proteins that catalyze a variety of oxidative reactions of a large number of structurally different endogenous and exogenous compounds in organisms from all major domains of life. CYPs bind their diverse ligands in a buried, hydrophobic active site, which is accessed through a substrate access channel formed by two flexible helices and their connecting loop.