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Gene Review

CYP2A13  -  cytochrome P450, family 2, subfamily A,...

Homo sapiens

Synonyms: CPAD, CYP2A, CYPIIA13, Cytochrome P450 2A13
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Disease relevance of CYP2A13

  • Together, these findings suggest that CYP2A13 plays important roles in xenobiotic toxicity and tobacco-related tumorigenesis in the human respiratory tract [1].
  • In this study, a CYP2A13 cDNA was prepared by RNA-PCR from human nasal mucosa and was translated using a baculovirus expression system [1].
  • There was little expression of CYP2A13 protein in different types of lung cancers [2].
  • Stratification analysis shows that the reduced risk of lung adenocarcinoma related to the variant CYP2A13 genotype was limited to smokers, especially light smokers (OR, 0.23; 95% CI, 0.08-0.68) but not nonsmokers or heavy smokers [3].
  • The K(m) and V(max) values for ABP N-hydroxylation by recombinant CYP2A13 in E. coli were 38.5 +/- 0.6 muM and 7.8 +/- 0.0 pmol/min/pmol CYP, respectively [4].

High impact information on CYP2A13


Chemical compound and disease context of CYP2A13


Biological context of CYP2A13


Anatomical context of CYP2A13

  • Consistent with the activity data, there was an approximately 800-fold difference in LC50 values of AFB1 (48-hr treatment) between Chinese hamster ovary (CHO) cells expressing CYP2A13 and CYP2A6 (50 nM versus 39 microM) [9].
  • Using this highly specific antibody for immunohistochemical staining, we detected a high level of CYP2A13 protein expression in the epithelial cells of human bronchus and trachea, but a rare distribution in the alveolar cells [2].
  • In conclusion, although the enzyme responsible for ABP N-hydroxylation in human bladder microsomes could not be determined, we found that CYP2A13 metabolically activates ABP [4].
  • The prenatal expression of the CYP2A proteins in the olfactory mucosa suggests potential risks of developmental toxicity from maternally derived xenobiotics, since both CYP2A6 and CYP2A13 are known to be efficient in the metabolic activation of tobacco-specific nitrosamines and other respiratory toxicants [10].
  • Since CYP2A13 is hardly expressed in human livers, the contribution of CYP2A13 to the nicotine N-demethylation in human liver microsomes would be negligible [11].

Associations of CYP2A13 with chemical compounds


Other interactions of CYP2A13

  • All three transcripts (CYP2A6, CYP2A7, and CYP2A13) were found to be present in liver [14].
  • The K(m) and V(max) values by recombinant CYP1A2 were 9.9 +/- 0.9 muM and 39.6 +/- 0.9 pmol/min/pmol CYP, respectively, showing 20-fold higher intrinsic clearance than CYP2A13 [4].
  • Development of a real-time polymerase chain reaction-based method for the measurement of relative allelic expression and identification of CYP2A13 alleles with decreased expression in human lung [15].
  • A functionally significant coding single nucleotide polymorphism (C3375T) in exon 5 of CYP2A13, which results in an amino acid substitution of Arg 257 to Cys, has been recently reported to exist in White, Black, Hispanic, and Asian individuals, with the variant 3375T allele frequencies being 1.9%, 14.4%, 5.8% and 7.7%, respectively [16].

Analytical, diagnostic and therapeutic context of CYP2A13


  1. Human cytochrome P450 CYP2A13: predominant expression in the respiratory tract and its high efficiency metabolic activation of a tobacco-specific carcinogen, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone. Su, T., Bao, Z., Zhang, Q.Y., Smith, T.J., Hong, J.Y., Ding, X. Cancer Res. (2000) [Pubmed]
  2. CYP2A13 in Human Respiratory Tissues and Lung Cancers: An Immunohistochemical Study with A New Peptide-Specific Antibody. Zhu, L.R., Thomas, P.E., Lu, G., Reuhl, K.R., Yang, G.Y., Wang, L.D., Wang, S.L., Yang, C.S., He, X.Y., Hong, J.Y. Drug Metab. Dispos. (2006) [Pubmed]
  3. Substantial reduction in risk of lung adenocarcinoma associated with genetic polymorphism in CYP2A13, the most active cytochrome P450 for the metabolic activation of tobacco-specific carcinogen NNK. Wang, H., Tan, W., Hao, B., Miao, X., Zhou, G., He, F., Lin, D. Cancer Res. (2003) [Pubmed]
  4. CYP2A13 expressed in human bladder metabolically activates 4-aminobiphenyl. Nakajima, M., Itoh, M., Sakai, H., Fukami, T., Katoh, M., Yamazaki, H., Kadlubar, F.F., Imaoka, S., Funae, Y., Yokoi, T. Int. J. Cancer (2006) [Pubmed]
  5. A genetic polymorphism in coumarin 7-hydroxylation: sequence of the human CYP2A genes and identification of variant CYP2A6 alleles. Fernandez-Salguero, P., Hoffman, S.M., Cholerton, S., Mohrenweiser, H., Raunio, H., Rautio, A., Pelkonen, O., Huang, J.D., Evans, W.E., Idle, J.R. Am. J. Hum. Genet. (1995) [Pubmed]
  6. Genetic polymorphisms of the human CYP2A13 gene: identification of single-nucleotide polymorphisms and functional characterization of an Arg257Cys variant. Zhang, X., Su, T., Zhang, Q.Y., Gu, J., Caggana, M., Li, H., Ding, X. J. Pharmacol. Exp. Ther. (2002) [Pubmed]
  7. CYP2A13-catalysed coumarin metabolism: comparison with CYP2A5 and CYP2A6. von Weymarn, L.B., Murphy, S.E. Xenobiotica (2003) [Pubmed]
  8. The Missense Genetic Polymorphisms of Human CYP2A13: Functional Significance in Carcinogen Activation and Identification of A Null Allelic Variant. Wang, S.L., He, X.Y., Shen, J., Wang, J.S., Hong, J.Y. Toxicol. Sci. (2006) [Pubmed]
  9. Efficient activation of aflatoxin B1 by cytochrome P450 2A13, an enzyme predominantly expressed in human respiratory tract. He, X.Y., Tang, L., Wang, S.L., Cai, Q.S., Wang, J.S., Hong, J.Y. Int. J. Cancer (2006) [Pubmed]
  10. Immunoblot analysis and immunohistochemical characterization of CYP2A expression in human olfactory mucosa. Chen, Y., Liu, Y.Q., Su, T., Ren, X., Shi, L., Liu, D., Gu, J., Zhang, Q.Y., Ding, X. Biochem. Pharmacol. (2003) [Pubmed]
  11. CYP2A6 AND CYP2B6 are involved in nornicotine formation from nicotine in humans: interindividual differences in these contributions. Yamanaka, H., Nakajima, M., Fukami, T., Sakai, H., Nakamura, A., Katoh, M., Takamiya, M., Aoki, Y., Yokoi, T. Drug Metab. Dispos. (2005) [Pubmed]
  12. Inactivation of CYP2A6 and CYP2A13 during nicotine metabolism. von Weymarn, L.B., Brown, K.M., Murphy, S.E. J. Pharmacol. Exp. Ther. (2006) [Pubmed]
  13. Identification of Val117 and Arg372 as critical amino acid residues for the activity difference between human CYP2A6 and CYP2A13 in coumarin 7-hydroxylation. He, X.Y., Shen, J., Hu, W.Y., Ding, X., Lu, A.Y., Hong, J.Y. Arch. Biochem. Biophys. (2004) [Pubmed]
  14. Expression of CYP2A genes in human liver and extrahepatic tissues. Koskela, S., Hakkola, J., Hukkanen, J., Pelkonen, O., Sorri, M., Saranen, A., Anttila, S., Fernandez-Salguero, P., Gonzalez, F., Raunio, H. Biochem. Pharmacol. (1999) [Pubmed]
  15. Development of a real-time polymerase chain reaction-based method for the measurement of relative allelic expression and identification of CYP2A13 alleles with decreased expression in human lung. Zhang, X., Caggana, M., Cutler, T.L., Ding, X. J. Pharmacol. Exp. Ther. (2004) [Pubmed]
  16. Arg257Cys polymorphism of CYP2A13 in a Chinese population. Cheng, X.Y., Chen, G.L., Zhang, W.X., Zhou, G., Wang, D., Zhou, H.H. Clin. Chim. Acta (2004) [Pubmed]
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