King H W, Osborne M R, Brookes P
Chem Biol Interact. 1979 Mar;24(3):345-53. doi: 10.1016/0009-2797(79)90082-6.
The previously reported reaction at N2- and N7- of guanine following addition of 7 alpha,8 beta-dihydroxy-9 beta, 10 beta-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (anti-BPDE) to an aqueous solution of DNA has been studied in more detail. The extent of reaction and the relative yields of N2- and N7-products was measured over the range of pH 4--7. The depurination following reaction at the N7-position of guanine was found to have a half-life of 3 h. Reaction of the isomeric 7 alpha,8 beta-dihydroxy-9 alpha, 10 alpha-epoxy-7,8,9,10-tetrahydrobenzo[a]-pyrene (syn-BPDE) with DNA gave the expected N2- and no N7-guanine product. When either benzo[a]pyrene or anti-BPDE was added to mouse embryo or Chinese hamster V79 cells respectively, a major N2-guanine product and a very minor adenine product were isolated from the DNA, but no N7-guanine product was detected.
此前有报道称，在DNA水溶液中加入7α,8β-二羟基-9β,10β-环氧-7,8,9,10-四氢苯并[a]芘（反式BPDE）后，鸟嘌呤的N2和N7位会发生反应，对此已进行了更详细的研究。在pH值4至7的范围内，测定了反应程度以及N2和N7产物的相对产率。发现鸟嘌呤N7位反应后的脱嘌呤半衰期为3小时。异构体7α,8β-二羟基-9α,10α-环氧-7,8,9,10-四氢苯并[a]芘（顺式BPDE）与DNA反应，生成了预期的N2鸟嘌呤产物，未生成N7鸟嘌呤产物。当分别将苯并[a]芘或反式BPDE添加到小鼠胚胎或中国仓鼠V79细胞中时，从DNA中分离出一种主要的N2鸟嘌呤产物和一种非常少量的腺嘌呤产物，但未检测到N7鸟嘌呤产物。
