THE HUMAN DRUG-METABOLIZING CYTOCHROMES P450

The superfamily of heme-thiolate proteins known as the cytochromes P45 0 if responsible for the oxidative metabolism of the majority of drugs . Thus, the phenotypes of individuals with respect to their levels of catalytically active cytochromes P450 determines to a large part the s ubstantial interindividual variation observed in the metabolic clearan ce of drugs. Over the past IO years IS different human cytochromes P45 0 involved in drug metabolism have been isolated and characterized to varying degrees. This brief review discusses the characterization of t hese cytochromes P450 and how this knowledge has been used by the phar maceutical industry to aid in the development of new drugs.