Indirect Carcinogen Cytochrome P-450(CYP): phase I precarcinogen enzymes Jact by adding atom onto the substrate inducible by polycyclic aromatic and chlorinated hydrocarbons Proximate carcinogen Largely responsible for the metabolic activation and detoxication Phase ii enzymes: act on oxidized substrates Ultimate carcinogen methyltransferases, acetyltransferases glutathione transferases, uridine 5 diphosphoglucuronosyl transferases sulfotransferases, nicotinamide-adenine dinucleotide(NAD)-and nicotinamide-adenine dinucleotide phosphate (NADP)-dependent alcohol, aldehyde and steroid dehydrogenases, quinone reductases NADPH diaphorase, azo reductases, aldoketoreductases transaminases, esterases, and hydrolasesIndirect Carcinogen precarcinigen Proximate carcinigen Ultimate carcinigen Cytochrome P-450 (CYP) : phase I enzymes ❑act by adding O atom onto the substrate ❑inducible by polycyclic aromatic and chlorinated hydrocarbons. ❑largely responsible for the metabolic activation and detoxication. Phase II enzymes: act on oxidized substrates methyltransferases, acetyltransferases, glutathione transferases, uridine 5'- diphosphoglucuronosyl transferases, sulfotransferases, nicotinamide-adenine dinucleotide (NAD)- and nicotinamide-adenine dinucleotide phosphate (NADP)-dependent alcohol, aldehyde and steroid dehydrogenases, quinone reductases, NADPH diaphorase, azo reductases, aldoketoreductases, transaminases, esterases, and hydrolases