CYP2C19（cytochrome P450 family 2 subfamily C member 19），癌症关联基因，基因ID：1557，该基因编码细胞色素p450酶超家族的一个成员。细胞色素p450蛋白是一种单加氧酶，催化药物代谢和胆固醇、类固醇等脂类的合成。这种蛋白质定位于内质网，已知能代谢许多外源性物质，包括抗惊厥药物美苯妥英、奥美拉唑、地西泮和一些巴比妥类药物。该基因的多态性与代谢苯妥英钠的可变能力有关，即代谢不良和广泛的代谢表型。该基因位于10q24号染色体上的细胞色素p450基因簇内。[由RefSeq提供，2008年7月]This gene encodes a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol， steroids and other lipids. This protein localizes to the endoplasmic reticulum and is known to metabolize many xenobiotics， including the anticonvulsive drug mephenytoin， omeprazole， diazepam and some barbiturates. Polymorphism within this gene is associated with variable ability to metabolize mephenytoin， known as the poor metabolizer and extensive metabolizer phenotypes. The gene is located within a cluster of cytochrome P450 genes on chromosome 10q24. [provi。