Alkylation and oxidative-DNA damage repair activity in blood leukocytes of smokers and non-smokers.

The levels of 3 DNA repair enzymes involved in alkylation and oxidative DNA damage repair in human peripheral blood leukocytes were measured in 20 smokers and 17 non-smokers. No differences in O6-alkylguanine-DNA-alkyltransferase (AGT) activity were found between the 2 groups and the AGT distribution within the population appeared to be unimodal. In contrast, the mean activities of both the methylpurine (MeP)- and the 2-6-diamino-4-hydroxy-5N formamidopyrimidine (FaPy)-DNA glycosylases were higher in the smokers, although only the difference between the MeP-DNA glycosylase means was statistically significant.