TY - JOUR T1 - Comparison of monooxygenase activities and cytochrome P-450 isozyme concentrations in human liver microsomes. JF - Drug Metabolism and Disposition JO - Drug Metab Dispos SP - 437 LP - 442 VL - 14 IS - 4 AU - P H Beaune AU - P G Kremers AU - L S Kaminsky AU - J De Graeve AU - A Albert AU - F P Guengerich Y1 - 1986/07/01 UR - http://dmd.aspetjournals.org/content/14/4/437.abstract N2 - Concentrations of three human liver microsomal cytochrome P-450 isozymes and 20 different monooxygenase activities were determined in human liver microsomal preparations. The results of correlation analysis suggest that: there are important variations in the amounts of the three cytochrome P-450 isozymes measured, particularly P-450(8) and P-450(9); aldrin epoxidase, d-benzphetamine N-demethylase, and S-warfarin 4-hydroxylase activities are linked to cytochrome P-450(5); aryl hydrocarbon (benzo(a)pyrene) hydroxylase and 4-nitroanisole-O-demethylase activities are linked to P-450(8); hydroxylations at the 4'-, 6-, 7-, and 8-positions of R-warfarin are closely linked to each other but are not correlated with other measured monooxygenase activities or P-450 isozyme levels; and P-450(9) is not related to any of the catalytic activities tested. Thus, certain monooxygenase activities can be attributed to specific cytochrome P-450 isozymes. This approach should be useful in suggesting the roles of different cytochromes P-450 in drug metabolism in man which can be further examined using in vitro and in vivo methods. ER -