Waters L C, Nix C E, Epler J L
Chem Biol Interact. 1983 Aug 15;46(1):55-66. doi: 10.1016/0009-2797(83)90006-6.
The relationship between dimethylnitrosamine (DMN) demethylase activity and DMN-induced mutagenesis was investigated in Drosophila melanogaster. The activity of DMN-demethylase was at least 10-fold greater in the Hikone-R strain than in three other Drosophila strains. However, the sex-linked recessive lethal (SLRL) mutations induced by DMN in the four strains differed by less than 2-fold. Several possibilities to explain the lack of correlation between DMN-demethylase activity and DMN-induced mutations were tested and eliminated. They include: (i) the presence of inhibitors of DMN-demethylase in extracts of low-activity strains, (ii) a sex bias in the Hikone-R strain in which the enzyme activity is confined to the females, (iii) the possibility that DMN treatment induces DMN-demethylase activity in the low-activity strains and (iv) the possibility that Hikone-R has a much more efficient DNA repair system than the other strains. The results are discussed in terms of what is known about the role of DMN-demethylase in the metabolic activation of DMN in other systems.
在黑腹果蝇中研究了二甲基亚硝胺（DMN）脱甲基酶活性与DMN诱导的诱变之间的关系。DMN脱甲基酶在彦根-R品系中的活性至少比其他三个果蝇品系高10倍。然而，DMN在这四个品系中诱导的性连锁隐性致死（SLRL）突变差异不到2倍。对几种解释DMN脱甲基酶活性与DMN诱导的突变之间缺乏相关性的可能性进行了测试并排除。它们包括：（i）低活性品系提取物中存在DMN脱甲基酶抑制剂；（ii）彦根-R品系中存在性别偏差，其中酶活性仅限于雌性；（iii）DMN处理在低活性品系中诱导DMN脱甲基酶活性的可能性；（iv）彦根-R品系比其他品系具有更高效的DNA修复系统的可能性。根据已知的DMN脱甲基酶在其他系统中DMN代谢活化中的作用对结果进行了讨论。
