A cytochrome P450 monooxygenase involved in the metabolism of endogenous polyunsaturated fatty acids (PUFAs). Mechanistically, uses molecular oxygen inserting one oxygen atom into a substrate, and reducing the second into a water molecule, with two electrons provided by NADPH via cytochrome P450 reductase (CPR; NADPH-ferrihemoprotein reductase). Catalyzes the hydroxylation of carbon hydrogen bonds, with preference for omega-2 position. Metabolizes (5Z,8Z,11Z,14Z)-eicosatetraenoic acid (arachidonate) toward 18-hydroxy arachidonate (PubMed:11162607). Catalyzes the epoxidation of double bonds of PUFAs such as docosapentaenoic and docosahexaenoic acids (PubMed:16112640). Has low omega-hydroxylase activity toward leukotriene B4 and arachidonate (PubMed:11162645). Involved in the metabolism of xenobiotics. Catalyzes the hydroxylation of the antihistamine drug ebastine (PubMed:11162645). an organic molecule + O2 + reduced [NADPH--hemoprotein reductase] = an alcohol + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] (5Z,8Z,11Z,14Z)-eicosatetraenoate + O2 + reduced [NADPH--hemoprotein reductase] = 18-hydroxy-(5Z,8Z,11Z,14Z)-eicosatetraenoate + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] (7Z,10Z,13Z,16Z,19Z)-docosapentaenoate + O2 + reduced [NADPH--hemoprotein reductase] = 10,11-epoxy-(7Z,13Z,16Z,19Z)-docosatetraenoate + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] (7Z,10Z,13Z,16Z,19Z)-docosapentaenoate + O2 + reduced [NADPH--hemoprotein reductase] = 13,14-epoxy-(7Z,10Z,16Z,19Z)-docosatetraenoate + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] (7Z,10Z,13Z,16Z,19Z)-docosapentaenoate + O2 + reduced [NADPH--hemoprotein reductase] = 16,17-epoxy-(7Z,10Z,13Z,19Z)-docosatetraenoate + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] (7Z,10Z,13Z,16Z,19Z)-docosapentaenoate + O2 + reduced [NADPH--hemoprotein reductase] = 19,20-epoxy-(7Z,10Z,13Z,16Z)-docosatetraenoate + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] (4Z,7Z,10Z,13Z,16Z,19Z)-docosahexaenoate + O2 + reduced [NADPH--hemoprotein reductase] = 10,11-epoxy-(4Z,7Z,13Z,16Z,19Z)-docosapentaenoate + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] (4Z,7Z,10Z,13Z,16Z,19Z)-docosahexaenoate + O2 + reduced [NADPH--hemoprotein reductase] = 13,14-epoxy-(4Z,7Z,10Z,16Z,19Z)-docosapentaenoate + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] (4Z,7Z,10Z,13Z,16Z,19Z)-docosahexaenoate + O2 + reduced [NADPH--hemoprotein reductase] = 16,17-epoxy-(4Z,7Z,10Z,13Z,19Z)-docosapentaenoate + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] (4Z,7Z,10Z,13Z,16Z,19Z)-docosahexaenoate + O2 + reduced [NADPH--hemoprotein reductase] = 19,20-epoxy-(4Z,7Z,10Z,13Z,16Z)-docosapentaenoate + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] Lipid metabolism; arachidonate metabolism. Expressed in small intestine, liver, colon and heart. Belongs to the cytochrome P450 family. Extended N-terminus.