Washington W J, Dunn W C, Generoso W M, Mitra S
Biology Division, Oak Ridge National Laboratory, TN 37831.
Mutat Res. 1988 Mar-Apr;207(3-4):165-9. doi: 10.1016/0165-7992(88)90082-6.
Two stocks of mice, hybrid (C3H X 101)F1 and inbred SEC/R1, were compared for 3-methyladenine-DNA N-glycosylase activity which is involved in removal of 3-methyladenine, 7-methylguanine and some other N-methylpurines in DNA, in cell-free extracts of different tissues. Based on activity measured both per unit weight of tissue and per mass DNA, there is a significant organ-specific and stock-specific difference in N-glycosylase activity over a range of 0.5-8.7 fmoles of 3-methyladenine released per h at 37 degrees C per micrograms DNA of tissue extract. On a per cell basis, the repair activity for 3-methyladenine is the highest in stomach in both stocks. The tissue can be arranged in order of decreasing activity of glycolytic removal as stomach greater than kidney greater than lung greater than liver greater than spleen greater than brain greater than ovary for SEC/R1 mice and stomach greater than kidney greater than ovary greater than spleen, lung and brain greater than liver for the hybrid mice. For all tissues except ovary, SEC/R1 mice have 1.5-4-fold higher specific N-glycosylase activity than (C3H X 101)F1 mice. In contrast, the ovary of SEC/R1 stock has about half as much enzyme activity as that of the hybrid stock.
比较了两群小鼠，即杂种（C3H×101）F1和近交系SEC/R1，检测了不同组织的无细胞提取物中3-甲基腺嘌呤-DNA N-糖苷酶的活性，该酶参与去除DNA中的3-甲基腺嘌呤、7-甲基鸟嘌呤和其他一些N-甲基嘌呤。根据每单位组织重量和每单位质量DNA所测得的活性，在37℃下，每微克组织提取物DNA每小时释放0.5-8.7飞摩尔3-甲基腺嘌呤的范围内，N-糖苷酶活性存在显著的器官特异性和群体特异性差异。以每个细胞为基础，两群小鼠中胃对3-甲基腺嘌呤的修复活性最高。对于SEC/R1小鼠，组织按糖酵解去除活性降低的顺序排列为：胃＞肾＞肺＞肝＞脾＞脑＞卵巢；对于杂种小鼠，顺序为：胃＞肾＞卵巢＞脾、肺和脑＞肝。除卵巢外，SEC/R1小鼠所有组织的特异性N-糖苷酶活性比（C3H×101）F1小鼠高1.5-4倍。相反，SEC/R1群体的卵巢酶活性约为杂种群体的一半。
