Nicotine, the main addictive compound in tobacco, is metabolically inactivated to cotinine primarily by the hepatic enzyme CYP2A6. Substantial genetic variation in the CYP2A6 gene contributes to large variation in nicotine metabolism which alters numerous smoking behaviours. The goal of this study was to identify and characterize novel CYP2A6 variants. The CYP2A6 gene from African American phenotypically slow nicotine metabolizers was sequenced. Seven novel non-synonymous variants were identified: 468G>A (V68M), 1767C>G (I149M), 3515G>A (R265Q), 3524T>C (I268T), 4406C>T (T303I), 5661G>A (E390K), 6531T>C (L462P). They were introduced into a cDNA expression construct where they displayed lower protein expression, reduced nicotine metabolism to cotinine, and/or reduced stability as evaluated by western blotting and enzymatic activity. Genotyping assays were developed and assessed in 512 African Americans. Allelic frequencies ranged from 0.1-0.6% with a collective genotype frequency of 3.2%. Here we identified novel variants with reduced/loss of CYP2A6 activity, increasing our understanding of CYP2A6 variability.
| Identifer | oai:union.ndltd.org:TORONTO/oai:tspace.library.utoronto.ca:1807/44055 |
| Date | 19 March 2014 |
| Creators | Piliguian, Mark |
| Contributors | Tyndale, Rachel |
| Source Sets | University of Toronto |
| Language | en_ca |
| Detected Language | English |
| Type | Thesis |
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