cytochrome P-450 system
Definition: a heterogeneous group of enzymes that catalyzes various oxidative reactions in the human liver, intestine, kidney, lung, and central nervous system. These enzymes are involved in the metabolism of many endogenous and exogenous substrates, including drugs, toxins, hormones, and natural plant products. Cytochrome P-450 enzymes are classified on the basis of chemical structure (amino acid sequencing). The designation of each enzyme is CYP followed by a numeral for the family to which it has been assigned, a letter for its subfamily, and sometimes a second numeral for the individual enzyme.