A cytochrome P450 monooxygenase involved in the metabolism of polyunsaturated fatty acids (PUFA) (PubMed:18577768, PubMed:19965576, PubMed:20972997). 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 (NADPH--hemoprotein reductase) (PubMed:18577768, PubMed:19965576, PubMed:20972997). Catalyzes the hydroxylation of carbon-hydrogen bonds. Hydroxylates PUFA specifically at the omega-1 position (PubMed:18577768). Catalyzes the epoxidation of double bonds of PUFA (PubMed:20972997, PubMed:19965576). Also metabolizes plant monoterpenes such as limonene. Oxygenates (R)- and (S)-limonene to produce carveol and perillyl alcohol (PubMed:11950794). Responsible for the metabolism of a number of therapeutic agents such as the anticonvulsant drug S-mephenytoin, omeprazole, proguanil, certain barbiturates, diazepam, propranolol, citalopram and imipramine. Hydroxylates fenbendazole at the 4' position (PubMed:23959307). an organic molecule + O2 + reduced [NADPH--hemoprotein reductase] = an alcohol + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] (5Z,8Z,11Z)-eicosatrienoate + O2 + reduced [NADPH--hemoprotein reductase] = 19-hydroxy-(5Z,8Z,11Z)-eicosatrienoate + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] (5Z,8Z,11Z,14Z)-eicosatetraenoate + O2 + reduced [NADPH--hemoprotein reductase] = 19-hydroxy-(5Z,8Z,11Z,14Z)-eicosatetraenoate + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] (5Z,8Z,11Z,14Z,17Z)-eicosapentaenoate + O2 + reduced [NADPH--hemoprotein reductase] = 19-hydroxy-(5Z,8Z,11Z,14Z,17Z)-eicosapentaenoate + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] (4Z,7Z,10Z,13Z,16Z,19Z)-docosahexaenoate + O2 + reduced [NADPH--hemoprotein reductase] = 21-hydroxy-(4Z,7Z,10Z,13Z,16Z,19Z)-docosahexaenoate + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] (5Z,8Z,11Z,14Z)-eicosatetraenoate + O2 + reduced [NADPH--hemoprotein reductase] = (8R,9S)-epoxy-(5Z,11Z,14Z)-eicosatrienoate + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] (5Z,8Z,11Z,14Z)-eicosatetraenoate + O2 + reduced [NADPH--hemoprotein reductase] = (11R,12S)-epoxy-(5Z,8Z,14Z)-eicosatrienoate + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] (5Z,8Z,11Z,14Z)-eicosatetraenoate + O2 + reduced [NADPH--hemoprotein reductase] = (11S,12R)-epoxy-(5Z,8Z,14Z)-eicosatrienoate + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] (5Z,8Z,11Z,14Z)-eicosatetraenoate + O2 + reduced [NADPH--hemoprotein reductase] = (14R,15S)-epoxy-(5Z,8Z,11Z)-eicosatrienoate + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] (5Z,8Z,11Z,14Z,17Z)-eicosapentaenoate + O2 + reduced [NADPH--hemoprotein reductase] = (17R,18S)-epoxy-(5Z,8Z,11Z,14Z)-eicosatetraenoate + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] (4Z,7Z,10Z,13Z,16Z,19Z)-docosahexaenoate + O2 + reduced [NADPH--hemoprotein reductase] = (19R,20S)-epoxy-(4Z,7Z,10Z,13Z,16Z)-docosapentaenoate + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] (4Z,7Z,10Z,13Z,16Z,19Z)-docosahexaenoate + O2 + reduced [NADPH--hemoprotein reductase] = (19S,20R)-epoxy-(4Z,7Z,10Z,13Z,16Z)-docosapentaenoate + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] (4R)-limonene + O2 + reduced [NADPH--hemoprotein reductase] = (1R,5S)-carveol + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] (4S)-limonene + O2 + reduced [NADPH--hemoprotein reductase] = (1S,5R)-carveol + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] (4S)-limonene + O2 + reduced [NADPH--hemoprotein reductase] = (4S)-perillyl alcohol + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] fenbendazole + O2 + reduced [NADPH--hemoprotein reductase] = 4'-hydroxyfenbendazole + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] Lipid metabolism; fatty acid metabolism. Terpene metabolism; (4R)-limonene degradation. P450 can be induced to high levels in liver and other tissues by various foreign compounds, including drugs, pesticides, and carcinogens. Genetic variation in CYP2C19 is responsible for poor drug metabolism [MIM:609535]. Individuals can be characterized as either extensive metabolizers (EM) or poor metabolizers (PM). The PM phenotype is inherited in an autosomal recessive manner, with the EM phenotype comprising both homozygous dominant and heterozygote genotypes. There are marked interracial differences in the frequency of this polymorphism. Poor metabolizers represent 2-5% of Caucasians, 13-23% of Asian populations, and as many as 38-79% of individuals of some of the islands of Polynesia and Micronesia. At least 38 different alleles are known including CYP2C19*1A, CYP2C19*1B, CYP2C19*1C, CYP2C19*2A (CYP2C19m1 or CYP2C19m1A), CYP2C19*2B (CYP2C19m1B), CYP2C19*2C (CYP2C19*21), CYP2C19*3A (CYP2C19m2), CYP2C19*3B (CYP2C19*20), CYP2C19*4 (CYP2C19m3), CYP2C19*5A (CYP2C19m4), CYP2C19*5B, CYP2C19*6, CYP2C19*7, CYP2C19*8, CYP2C19*9, CYP2C19*10, CYP2C19*11 CYP2C19*12, CYP2C19*13, CYP2C19*14 CYP2C19*15, CYP2C19*16, CYP2C19*18 and CYP2C19*19. Defective CYP2C19*2 and CYP2C19*3 alleles are characterized by a splice mutation and a stop codon, respectively, and account for most of the PM alleles. The sequence shown is that of allele CYP2C19*1A. Belongs to the cytochrome P450 family. P450-254C was originally listed as a separate gene (CYP2C17). Resequencing demonstrated that it is not a separate gene, but a chimera. The 5'-portion corresponds to a partial 2C18 clone, and the 3'-portion corresponds to a partial 2C19 clone. CYP2C19 alleles