Characterization of cytochrome P-450 2B6 in human liver microsomes

M Mimura, T Baba, H Yamazaki, S Ohmori, Y Inui, FJ Gonzalez, FP Guengerich and T Shimada

Osaka Prefectural Institute of Public Health, Japan.

A cytochrome P-450 (P-450) enzyme of the CYP2B subfamily was partially purified from human liver microsomes and characterized with respect to immunochemical properties, N-terminal amino acid sequence, and catalytic activities toward typical P-450 substrates. P-450 enzymes were monitored in chromatographic fractions by immunoblotting analysis using antibodies raised against a monkey P-450 2B, as well as several purified human P-450 enzymes. The final P-450 2B preparation thus obtained was contaminated with P-450 3A4, but an N-terminal amino acid sequence matching the sequence predicted from the CYP2B6 cDNA was obtained. The apparent M(r) of this protein was 48 kDa, and the migration on sodium dodecyl sulfate-polyacrylamide gel electrophoresis was the same as that of the P-450 2B6 protein expressed in a human lymphoblast cell line. Immunoblotting analysis of 50 human liver samples revealed that the protein band considered to be P-450 2B6 was detected in only 12 samples, with four of these having relatively high levels. Several activities toward typical P-450 substrates were determined in a reconstituted monooxygenase system containing partially purified P-450 2B6 and compared with those obtained using a highly purified preparation of P-450 3A4 enzyme; we found that most of the activities were similar in these preparations, except that the partially purified P-450 2B6 showed high rates of activation of the mutagens 6-aminochrysene and 3-methoxy-4-aminoazobenzene to genotoxic metabolites in Salmonella typhimurium NM2009 strain.(ABSTRACT TRUNCATED AT 250 WORDS)

Volume 21, Issue 6, pp. 1048-1056, 11/01/1993
Copyright © 1993 by American Society for Pharmacology and Experimental Therapeutics

This article has been cited by other articles:

				P. J. Murphy The Development of Drug Metabolism Research as Expressed in the Publications of ASPET: Part 3, 1984-2008 Drug Metab. Dispos., October 1, 2008; 36(10): 1977 - 1982. [Abstract] [Full Text] [PDF]

				Y. Duan, A. Catana, Y. Meng, N. Yamamoto, S. He, S. Gupta, S. S. Gambhir, and M. A. Zern Differentiation and Enrichment of Hepatocyte-Like Cells from Human Embryonic Stem Cells In Vitro and In Vivo Stem Cells, December 1, 2007; 25(12): 3058 - 3068. [Abstract] [Full Text] [PDF]

				S. J. Gardiner and E. J. Begg Pharmacogenetics, Drug-Metabolizing Enzymes, and Clinical Practice Pharmacol. Rev., September 1, 2006; 58(3): 521 - 590. [Abstract] [Full Text] [PDF]

				M. Turpeinen, R. Nieminen, T. Juntunen, P. Taavitsainen, H. Raunio, and O. Pelkonen SELECTIVE INHIBITION OF CYP2B6-CATALYZED BUPROPION HYDROXYLATION IN HUMAN LIVER MICROSOMES IN VITRO Drug Metab. Dispos., June 1, 2004; 32(6): 626 - 631. [Abstract] [Full Text] [PDF]

				H. Wang, S. R. Faucette, D. Gilbert, S. L. Jolley, T. Sueyoshi, M. Negishi, and E. L. LeCluyse Glucocorticoid Receptor Enhancement of Pregnane X Receptor-Mediated CYP2B6 Regulation in Primary Human Hepatocytes Drug Metab. Dispos., May 1, 2003; 31(5): 620 - 630. [Abstract] [Full Text] [PDF]

				H. Jinno, T. Tanaka-Kagawa, A. Ohno, Y. Makino, E. Matsushima, N. Hanioka, and M. Ando Functional Characterization of Cytochrome P450 2B6 Allelic Variants Drug Metab. Dispos., April 1, 2003; 31(4): 398 - 403. [Abstract] [Full Text] [PDF]

				P. W. Fan, C. Gu, S. A. Marsh, and J. C. Stevens Mechanism-Based Inactivation of Cytochrome P450 2B6 by a Novel Terminal Acetylene Inhibitor Drug Metab. Dispos., January 1, 2003; 31(1): 28 - 36. [Abstract] [Full Text] [PDF]

				J. M. Rae, N. V. Soukhova, D. A. Flockhart, and Z. Desta Triethylenethiophosphoramide Is a Specific Inhibitor of Cytochrome P450 2B6: Implications for Cyclophosphamide Metabolism Drug Metab. Dispos., May 1, 2002; 30(5): 525 - 530. [Abstract] [Full Text] [PDF]

				U. M. Kent, D. E. Mills, R. V. Rajnarayanan, W. L. Alworth, and P. F. Hollenberg Effect of 17-alpha -Ethynylestradiol on Activities of Cytochrome P450 2B (P450 2B) Enzymes: Characterization of Inactivation of P450s 2B1 and 2B6 and Identification of Metabolites J. Pharmacol. Exp. Ther., February 1, 2002; 300(2): 549 - 558. [Abstract] [Full Text] [PDF]

				A. L. Upthagrove and W. L. Nelson Carbinolamines, Imines, and Oxazolidines from Fluorinated Propranolol Analogs. 19F NMR and Mass Spectral Characterization and Evidence for Formation as Intermediates in Cytochrome P450-Catalyzed N-Dealkylation Drug Metab. Dispos., August 1, 2001; 29(8): 1114 - 1122. [Abstract] [Full Text] [PDF]

				V. Subrahmanyam, A. B. Renwick, D. G. Walters, P. J. Young, R. J. Price, A. P. Tonelli, and B. G. Lake Identification of Cytochrome P-450 Isoforms Responsible for cis-Tramadol Metabolism in Human Liver Microsomes Drug Metab. Dispos., August 1, 2001; 29(8): 1146 - 1155. [Abstract] [Full Text] [PDF]

				M. Miyazawa, M. Shindo, and T. Shimada Oxidation of 1,8-Cineole, the Monoterpene Cyclic Ether Originated From Eucalyptus Polybractea, by Cytochrome P450 3A Enzymes in Rat and Human Liver Microsomes Drug Metab. Dispos., February 1, 2001; 29(2): 200 - 205. [Abstract] [Full Text]

				L. M. Hesse, K. Venkatakrishnan, M. H. Court, L. L. von Moltke, S. X. Duan, R. I. Shader, and D. J. Greenblatt CYP2B6 Mediates the In Vitro Hydroxylation of Bupropion: Potential Drug Interactions with Other Antidepressants Drug Metab. Dispos., October 1, 2000; 28(10): 1176 - 1183. [Abstract] [Full Text] [PDF]

				S. R. Faucette, R. L. Hawke, E. L. Lecluyse, S. S. Shord, B. Yan, R. M. Laethem, and C. M. Lindley Validation of Bupropion Hydroxylation as a Selective Marker of Human Cytochrome P450 2B6 Catalytic Activity Drug Metab. Dispos., October 1, 2000; 28(10): 1222 - 1230. [Abstract] [Full Text] [PDF]

				T. Shimada, F. Tsumura, and H. Yamazaki Prediction of Human Liver Microsomal Oxidations of 7-Ethoxycoumarin and Chlorzoxazone with Kinetic Parameters of Recombinant Cytochrome P-450 Enzymes Drug Metab. Dispos., November 1, 1999; 27(11): 1274 - 1280. [Abstract] [Full Text]

				T. L. Domanski, K. M. Schultz, F. Roussel, J. C. Stevens, and J. R. Halpert Structure-Function Analysis of Human Cytochrome P-450 2B6 Using a Novel Substrate, Site-Directed Mutagenesis, and Molecular Modeling J. Pharmacol. Exp. Ther., September 1, 1999; 290(3): 1141 - 1147. [Abstract] [Full Text]

				D. M. Stresser and D. Kupfer Monospecific Antipeptide Antibody to Cytochrome P-450 2B6 Drug Metab. Dispos., April 1, 1999; 27(4): 517 - 525. [Abstract] [Full Text]

				H. Yamazaki, K. Inoue, P. M. Shaw, W. J. Checovich, F. P. Guengerich, and T. Shimada Different Contributions of Cytochrome P450 2C19 and 3A4 in the Oxidation of Omeprazole by Human Liver Microsomes: Effects of Contents of These Two Forms in Individual Human Samples J. Pharmacol. Exp. Ther., November 1, 1997; 283(2): 434 - 442. [Abstract] [Full Text]

				J. C. Stevens, R. B. White, S. H. Hsu, and M. Martinet Human Liver CYP2B6-Catalyzed Hydroxylation of RP 73401 J. Pharmacol. Exp. Ther., September 1, 1997; 282(3): 1389 - 1395. [Abstract] [Full Text]

				E. L. Code, C. L. Crespi, B. W. Penman, F. J. Gonzalez, T. K. H. Chang, and D. J. Waxman Human Cytochrome P4502B6. Interindividual Hepatic Expression, Substrate Specificity, and Role in Procarcinogen Activation Drug Metab. Dispos., August 1, 1997; 25(8): 985 - 993. [Abstract] [Full Text]

				D. K. Spracklin, D. C. Hankins, J. M. Fisher, K. E. Thummel, and E. D. Kharasch Cytochrome P450 2E1 is the Principal Catalyst of Human Oxidative Halothane Metabolism in Vitro J. Pharmacol. Exp. Ther., April 1, 1997; 281(1): 400 - 411. [Abstract] [Full Text]

				H. Yamazaki, K. Inoue, C. G. Turvy, F. P. Guengerich, and T. Shimada Effects of Freezing, Thawing, and Storage of Human Liver Samples on the Microsomal Contents and Activities of Cytochrome P450 Enzymes Drug Metab. Dispos., February 1, 1997; 25(2): 168 - 174. [Abstract] [Full Text]