CYP3As catalyze nifedipine oxidation in pig liver microsomes: Enzyme kinetics, inhibition and functional expression

Cytochrome P450 (CYP) 3As have received much attention because of their importance in drug metabolism. However, information on CYP3As in pigs is still largely incomplete. Herein, we focused on the involvement of CYP3As in nifedipine oxidation in pig liver microsomes. Enzyme kinetics, inhibition and immunochemical studies indicated that CYP3As might catalyze nifedipine oxidation and that ketoconazole could strongly inhibit this reaction in a noncompetitive and time-dependent manner. Furthermore, pig CYP3A46, showing the highest amino acid sequence identity to human CYP3A4, exhibited nifedipine oxidation activity. Collectively, these results provide strong evidence that CYP3As catalyze nifedipine oxidation in pig liver microsomes.

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► Ketoconazole noncompetitively and time-dependently inhibited nifedipine oxidation in pig liver microsomes.
► Recombinant CYP3A46 exhibited nifedipine oxidation activity.
► CYP3As catalyze nifedipine oxidation in pig liver microsomes.