CYP2C19是CYP450酶第二亞家族中的重要成員，是人體重要的藥物代謝酶，在肝臟中有很多表達。CYP2C19基因座位於染色體區10q24.2上，都由9個外顯子構成。CYP2C19與CYP2C9有92%的序列同源性。
重要性,多態性,
重要性
在2002年最多常用的200種處方藥物中，大部分由P450酶負責代謝。而P450酶負責代謝的藥物中，12%由CYP2C19代謝。由CYP2C19代謝的藥物如下。
Drugs and other agents whose metabolic pathway cosegregates with the activity ofcytochrome P450 2C19invitroand/orin vivo
Proton pump inhibitors Omeprazole 5-hydroxylation;Lansoprazole 5-hydroxylation; PantoprazoleO-demethylation;RabeprazoleN-demethylation Anticonvulsants, hypnosedatives, muscle relaxants Phenytoin 3’- and 4’-hydroxylation;(S)-Mephenytoin and nirvanol 4′-hydroxylation;Methylphenytoin 4′-hydroxylation;DiazepamN-demethylation (activation);Desmethyldiazepam hydroxylation;FlunitrazepamN-demethylation; Phenobarbitalp-hydroxylation;(R)-Hexobarbital 3′-hydroxylation; (R)-Mephobarbital 4-hydroxylation;CarisoprodolN-demethylation Anti-infectives Proguanil cyclisation (activation); Chlorproguanil cyclisation (activation); Nelfinavir hydroxylation (activation) Antidepressants CitalopramN-demethylation; FluoxetineN-demethylation; SertralineN-demethylation; VenlafaxineO-demethylation (activation); ImipramineN-demethylation; ClomipramineN-demethylation; Trimipramine; AmitriptylineN-demethylation; Nortriptyline demethylation; MoclobemideC-hydroxylation Others (mainlyin vitroevidence) Thioridazine Propranolol side-chain oxidation Tolbutamide 4-hydroxylation (R)-Warfarin 8-hydroxylation Progesterone 21-hydroxylation Testosterone oxidation at 17-position Desogestrel 3α-hydroxylation (activation) Cyclophosphamide 4-hydroxylation (active) Ifosfamide 4-hydroxylation (active) MethoxychlorO-demethylation (activation) |
多態性
CYP2C19具有很多SNP位點，在人類細胞色素P450等位基因命名法委員會（HumanCYPAllele NomenclatureCommittee）有詳盡的總結。最常見的是CYP2C19*2和CYP2C19*3。CYP2C19*2會導致轉錄蛋白的剪下突變失活，而CYP2C19*3能構成一個終止子，破壞轉錄蛋白的活性。據統計，CYP2C19*2和CYP2C19*3兩個突變位點能解釋幾乎100%的東亞人和85%的高加索人種的相關弱代謝遺傳缺陷，而其他兩種等位基因CYP2C19*4和CYP2C19*5主要在高加索人種中分布。大量證據證實，不同人種在CYP2C19的底物的代謝能力有很大差異；2–5%高加索人是弱代謝者，而13–23%的亞洲人是弱代謝者。這是一由於在亞洲人口中CYP2C19*2和CYP2C19*3等位基因的高頻率造成的。
