PTGIS（prostaglandin I2 synthase），癌症关联基因，基因ID：5740，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。然而，根据序列相似性而非功能相似性，该蛋白被认为是细胞色素p450超家族的成员。这种内质网膜蛋白催化前列腺素H2转化为前列腺素I2，一种有效的血管扩张剂和血小板聚集抑制剂前列环素及其生理拮抗剂血栓素a2的失衡有助于心肌梗死、中风和动脉粥样硬化的发生。[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. However， this protein is considered a member of the cytochrome P450 superfamily on the basis of sequence similarity rather than functional similarity. This endoplasmic reticulum membrane protein catalyzes the conversion of prostglandin H2 to prostacyclin (prostaglandin I2)， a potent vasodilator and inhibitor of platelet aggregation. An imbalance of prostacyclin and its physiological antagonist thromboxane A2 contribute to the development of myocardial i。