Comparative study of the metabolism of drug substrates by human cytochrome P450 3A4 expressed in bacterial, yeast and human lymphoblastoid cells
| Autor: | J B Houston, M. F. Abd-Ellah, J. Andrews, T. Friedberg, K. E. Kenworthy, N. L. Randolph, D. J. Carlile |
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| Rok vydání: | 2002 |
| Předmět: |
Adult
Male Midazolam Health Toxicology and Mutagenesis Saccharomyces cerevisiae Toxicology Dextromethorphan Biochemistry Isozyme Substrate Specificity Temazepam Cytochrome P-450 Enzyme System Escherichia coli Cytochrome P-450 CYP3A Humans Lymphocytes GABA Modulators Chromatography High Pressure Liquid Pharmacology Diazepam Dose-Response Relationship Drug biology CYP3A4 Lymphoblast Cytochrome P450 General Medicine Metabolism Middle Aged Recombinant Proteins In vitro Yeast Kinetics Liver Microsomes Liver biology.protein Microsome Female Excitatory Amino Acid Antagonists Protein Binding |
| Zdroj: | Xenobiotica. 32:937-947 |
| ISSN: | 1366-5928 0049-8254 |
| Popis: | 1. The aim was to compare the metabolic activity of human CYP3A4 expressed in bacteria (E. coli), yeast (S. cerevisiae) and human lymphoblastoid cells (hBl), with the native CYP3A4 activity observed in a panel of human livers. 2. Three CYP3A4 substrates were selected for study: dextromethorphan (DEM), midazolam (MDZ) and diazepam (DZ). The substrate metabolism in each of the four systems was characterized by deriving the kinetic parameters K(m) or S(50), V(max) and intrinsic clearance (CL(int)) or maximum clearance (CL(max)) from the kinetic profiles; the latter differing by 100-fold across the three substrates. 3. The K(m) or S(50) for the formation of metabolites 3-methoxymorphinan (MEM), 1'-hydroxymidazolam (1'-OH MDZ) and 3-hydroxydiazepam (3HDZ) compared well in all systems. For CYP3A4-mediated metabolism of DEM, MDZ and DZ, the V(max) for hBl microsomes were generally 2-9-fold higher than the respective yeast and human liver microsomes and E. coli membrane preparations, resulting in greater CL(int) or CL(max). In the case of 3HDZ formation, non-linear kinetics were observed for E. coli, hBl microsomes and human liver microsomes, whereas the kinetics observed for S. cerevisiae were linear. 4. The use of native human liver microsomes for drug metabolic studies will always be preferable. However, owing to the limited availability of human tissues, we find it is reasonable to use any of the recombinant systems described herein, since all three recombinant systems gave good predictions of the native human liver enzyme activities. |
| Databáze: | OpenAIRE |
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