Renard A, Lemaitre M, Verly W G
Biochimie. 1982 Aug-Sep;64(8-9):803-4. doi: 10.1016/s0300-9084(82)80132-6.
Disappearance of 7-ethylguanine and O6-ethylguanine lesions from nuclear DNA is observed on incubation of isolated rat liver nuclei previously treated with ethylnitrosourea. Free 7-ethylguanine but no free O6-ethylguanine is released in the medium. Incubation of methylated or ethylated DNA with chromatin proteins leads to the disappearance of O6-methylguanine or O6-ethylguanine from DNA; the methyl group or the ethyl group is transferred to proteins where it is accepted by cystein residues. Repair of O6-methylguanine and repair of O6-ethylguanine lesions in DNA consume a common reactant which is likely the acceptor protein. The repair does not seem however to be a simple bimolecular reaction between the O6-alkylguanine and the cystein of the acceptor protein.
在对先前用乙基亚硝基脲处理过的离体大鼠肝细胞核进行孵育时，可观察到核DNA中7-乙基鸟嘌呤和O6-乙基鸟嘌呤损伤的消失。培养基中释放出游离的7-乙基鸟嘌呤，但未释放出游离的O6-乙基鸟嘌呤。甲基化或乙基化的DNA与染色质蛋白一起孵育会导致DNA中的O6-甲基鸟嘌呤或O6-乙基鸟嘌呤消失；甲基或乙基会转移到蛋白质上，并被半胱氨酸残基接受。DNA中O6-甲基鸟嘌呤的修复和O6-乙基鸟嘌呤损伤的修复消耗一种常见反应物，该反应物可能是受体蛋白。然而，这种修复似乎不是O6-烷基鸟嘌呤与受体蛋白半胱氨酸之间简单的双分子反应。
