CYP3A4（cytochrome P450 family 3 subfamily A member 4），癌症关联基因，基因ID：1576，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、类固醇和其他脂质的合成。该蛋白定位于内质网，由糖皮质激素和一些药物诱导表达。这种酶参与了目前使用的大约一半药物的代谢，包括对乙酰氨基酚、可待因、环孢素A、地西泮和红霉素。这种酶也能代谢一些类固醇和致癌物。该基因是7q21.1染色体上一组细胞色素p450基因的一部分。以前人们认为另一个cyp3a基因cyp3a3存在；然而，现在人们认为这个序列代表cyp3a4的转录变体。另外，还发现了编码不同亚型的剪接转录变体。[由RefSeq提供，2011年2月]This gene encodes a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases that catalyze many reactions involved in drug metabolism and synthesis of cholesterol， steroids and other lipids. This protein localizes to the endoplasmic reticulum and its expression is induced by glucocorticoids and some pharmacological agents. This enzyme is involved in the metabolism of approximately half the drugs in use today， including acetaminophen， codeine， cyclosporin A， diazepam and erythromycin. The enzyme also metabolizes some steroids and carcinogens. This gen。