Many biochemical approaches have been
applied to the human cytochrome P450 enzymes, and
more than 20 different gene products have been characterized
with regard to their properties and catalytic
specifIcities. The complement of the various cytochrome
P450 enzymes in a given individual varies markedly, and
dramatic differences may be seen in drug metabolism,
pharmacological response, and susceptibility to toxic
effects. An understanding of the nature of the individual
cytochrome P450 enzymes and their regulation should be
useful in determining the most suitable animal models,
ascertaining risk from chemicals, and in avoiding undesirable
drug interactions. - Guengerich, F, P. Characterization
of human cytochrome P450 enzymes.