细胞色素P450（CYP）是混合功能氧化酶超家族中含有血红素的膜蛋白，可对各种外源性物质包括药物、致癌物和其他化合物及内源性底物（如类固醇、脂肪酸、前列腺素和胆红素等）进行生物转化。非结合胆红素能通过血脑屏障，当脑内胆红素水平过高，就会产生神经毒性。正常情况下，胆红素在肝内代谢，CYP是主要代谢酶之一。 CYP在脑内同样存在，并且能够代谢胆红素，减轻胆红素引起的神经元的损伤。“,”Cytochrome P450 ( CYP) is a membranin with hemocrystallin belonging to mixed function oxidase family,and effects on exogenous materials like drugs,carcinogens and other compound and endoge-nous substrates(such as steroids,fatty acids,prostaglandin and bilirubin) by biotransformation.Unconjugated bilirubin can pass the blood-brain barrier, and when brain bilirubin level is too high and neurotoxicity appears.Normally,bilirubin metabolizes in the liver,and CYP is one of the major metabolizing enzymes.There is CYP in the brain as well,which can metabolize bilirubin and lighten the nerve injury caused by bilirubin .