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Gene Review

Cyp2b2  -  cytochrome P450, family 2, subfamily b,...

Rattus norvegicus

Synonyms: CYPIIB2, Cyp2b-2, Cype, Cytochrome P450 2B2, Cytochrome P450 PB4, ...
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High impact information on Cyp2b2

  • Most significant of these differences was the relatively weak induction of CYPIIB1 but striking induction of CYPIIB2 by tamoxifen [1].
  • Thio-TEPA depletion and TEPA formation catalyzed by phenobarbital-induced liver microsomes were both inhibited by greater than 90% by antibodies selectively reactive with P-450 PB-4 (gene product IIB1), the major phenobarbital-inducible rat liver microsomal P-450 form, but not by antibodies inhibitory toward 7 other rat hepatic P-450s [2].
  • Oxidation of thio-TEPA to TEPA was also catalyzed by purified P-450 PB-4 (Km (app) 19 microM; Vmax (app) = 11 mol thio-TEPA metabolized/min/mol P-450 PB-4) following reconstitution of the cytochrome with NADPH P-450 reductase in a lipid environment [2].
  • These results demonstrate that, in vivo, phenobarbital induction and tissue-specific control requires interaction of regulatory elements far upstream of the core CYP2B2 promoter region and upstream of motifs indicated previously as determinants of phenobarbital responsiveness [3].
  • Expression in mouse tissues was analyzed for two series of rat CYP2B2 gene constructs, of 19 and 39 kilobase pairs total length, each containing the entire coding region, introns, and 3'-flanking sequences of CYP2B2, but differing in the respective lengths of 5'-flanking sequence [3].

Biological context of Cyp2b2

  • About 3 kb of the promoter region of the gene encoding cytochrome P-450 2B2 (CYP2B2) in the rat were sequenced and searched for potential cis-acting elements [4].
  • The use of a deletion series of this template in in vitro transcription assays, provided evidence that the BRE serves as a major cis-acting element in the (regulated) transcription activation of the CYP2B2 gene [4].
  • Although it is unclear whether P-450 PB-4 and P-450 PB-5 are separate gene products or are related by post-translational modifications, this present demonstration of closely related isozymic forms suggests the possible added complexity of microheterogeneity for this family of microsomal monooxygenases [5].
  • Very similar substrate specificity profiles were evident when the two isozymes were reconstituted with lipid, cytochrome P-450 reductase, and cytochrome b5 for oxidative metabolism of several xenobiotics, although P-450 PB-4 exhibited a higher specific catalytic activity (greater than or equal to 5-fold) with all substrates tested [5].
  • Null phenotype for cytochrome P450 2B2 in the rat results from a deletion of its structural gene [6].

Anatomical context of Cyp2b2

  • Fractionation of cell homogenates into cytosol and microsomes revealed that the P-450 PB-4-mediated activities are associated with the membrane fraction [7].
  • Homogenates prepared from the parental cell line V79, which does not express detectable levels of P-450 PB-4 or any other cytochrome P-450, exhibited no androgen 16 beta- or 16 alpha-hydroxylase activity [7].
  • Androgen hydroxylation catalysed by Chinese hamster fibroblast SD1 cells, which stably express cytochrome P-450 form PB-4, the rat P450IIB1 gene product, was assessed and compared to that catalysed by purified cytochrome P-450 PB-4 isolated from rat liver [7].
  • Xenobiotic induction of P-450 PB-4 (IIB1) and P-450c (IA1) and associated monooxygenase activities in primary cultures of adult rat hepatocytes [8].

Associations of Cyp2b2 with chemical compounds


Other interactions of Cyp2b2


Analytical, diagnostic and therapeutic context of Cyp2b2


  1. Effects of tamoxifen administration on the expression of xenobiotic metabolizing enzymes in rat liver. Nuwaysir, E.F., Dragan, Y.P., Jefcoate, C.R., Jordan, V.C., Pitot, H.C. Cancer Res. (1995) [Pubmed]
  2. Biotransformation of N,N',N''-triethylenethiophosphoramide: oxidative desulfuration to yield N,N',N''-triethylenephosphoramide associated with suicide inactivation of a phenobarbital-inducible hepatic P-450 monooxygenase. Ng, S.F., Waxman, D.J. Cancer Res. (1990) [Pubmed]
  3. Phenobarbital induction and tissue-specific expression of the rat CYP2B2 gene in transgenic mice. Ramsden, R., Sommer, K.M., Omiecinski, C.J. J. Biol. Chem. (1993) [Pubmed]
  4. Analysis of the promoter of the cytochrome P-450 2B2 gene in the rat. Hoffmann, M., Mager, W.H., Scholte, B.J., Civil, A., Planta, R.J. Gene Expr. (1992) [Pubmed]
  5. Phenobarbital-induced rat liver cytochrome P-450. Purification and characterization of two closely related isozymic forms. Waxman, D.J., Walsh, C. J. Biol. Chem. (1982) [Pubmed]
  6. Null phenotype for cytochrome P450 2B2 in the rat results from a deletion of its structural gene. Omiecinski, C.J., Ramsden, R., Rampersaud, A., Walz, F.G. Mol. Pharmacol. (1992) [Pubmed]
  7. Androgen hydroxylation catalysed by a cell line (SD1) that stably expresses rat hepatic cytochrome P-450 PB-4 (IIB1). Waxman, D.J., Lapenson, D.P., Morrissey, J.J., Park, S.S., Gelboin, H.V., Doehmer, J., Oesch, F. Biochem. J. (1989) [Pubmed]
  8. Xenobiotic induction of P-450 PB-4 (IIB1) and P-450c (IA1) and associated monooxygenase activities in primary cultures of adult rat hepatocytes. Jauregui, H.O., Ng, S.F., Gann, K.L., Waxman, D.J. Xenobiotica (1991) [Pubmed]
  9. The structure of phenobarbital-inducible rat liver cytochrome P-450 isoenzyme PB-4. Production and characterization of site-specific antibodies. Frey, A.B., Waxman, D.J., Kreibich, G. J. Biol. Chem. (1985) [Pubmed]
  10. Localization of a phenobarbital-responsive element (PBRE) in the 5'-flanking region of the rat CYP2B2 gene. Trottier, E., Belzil, A., Stoltz, C., Anderson, A. Gene (1995) [Pubmed]
  11. 3-(Trifluoromethyl)-3-(m-[125I]iodophenyl)diazirine photolabels a substrate-binding site of rat hepatic cytochrome P-450 form PB-4. Frey, A.B., Kreibich, G., Wadhera, A.B., Clarke, L., Waxman, D.J. Biochemistry (1986) [Pubmed]
  12. Structure-activity relationships for triphenylethylene antiestrogens on hepatic phase-I and phase-II enzyme expression. Nuwaysir, E.F., Dragan, Y.P., McCague, R., Martin, P., Mann, J., Jordan, V.C., Pitot, H.C. Biochem. Pharmacol. (1998) [Pubmed]
  13. Xenobiotic metabolizing enzymes are not restricted to parenchymal cells in rat liver. Steinberg, P., Lafranconi, W.M., Wolf, C.R., Waxman, D.J., Oesch, F., Friedberg, T. Mol. Pharmacol. (1987) [Pubmed]
  14. Matrix-assisted laser desorption mass spectrometry of cytochromes P450. Lewis, S., Korsmeyer, K.K., Correia, M.A. Rapid Commun. Mass Spectrom. (1993) [Pubmed]
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