Abstract: In the cytochrome P450(CYP) superfamily, cytochrome P4502A5(CYP2A5) is induced by a number of structural diverse of hepatotoxic compounds in the murine liver, plays a unique up-regulation in the process of hepatitis and hepatotoxicity. Researching the mechanism of expression and regulation, catalysis, induction or inhibition the metabolism of CYP2A5 gene, and chemical xenobiotics metabolism, play a key role in guiding the rational drug use of human clinical, preventing from cancer diseases, improving drug efficacy and reducing the side effects of drugs. This paper gives an overview of the characteristics of CYP2A5, the affecting factors and their relationship with the disease.

Key words: CYP2A5; coumarin 7-hydroxylase; tumor; nicotine