University of Toronto other research news
Canadian researchers published in Nature a genetic variation in an enzyme responsible for breaking down nicotine. Individuals who lack a fully functional enzyme that changes nicotine to cotinine may be protected against nicotine addiction. The researchers found that the frequency of individuals with impaired nicotine metabolism, that is, those who carried one or two of the null (less active) alleles of the enzyme, CYP2A6, was lower in smokers than in those who tried smoking but did not develop dependency (12.3 versus 19.6 percent, p<0.04). Those with one null allele smoked fewer cigarettes per week than smokers with two working alleles for the enzyme (129 versus 159 cigarettes per week, p< 0.02). In humans, 60 to 80 percent of nicotine delivered by smoking is metabolized to cotinine by CYP2A6. ...