Chetsanga C J, Lozon M, Makaroff C, Savage L
Biochemistry. 1981 Sep 1;20(18):5201-7. doi: 10.1021/bi00521a016.
A DNA glycosylase that excises 7-methylguanines with alkali-opened imidazole rings (formamidopyrimidines) from DNA has been purified more than 8000-fold from Escherichia coli cell extracts. The enzyme does not cleave 3-methyladenine, uracil, and intact 7-methylguanine from DNA. In assays containing pyrimidine analogues like oxauracil, 2,4,6-triaminopyrimidine, 2,5,6-triamino-2-hydroxypyrimidine sulfate, formamidopyrimidine, and 5-nitroso-2,4,6-triaminopyrimidine, only the two compounds showed end product inhibition of the enzyme. The enzyme has been named formamidopyrimidine-DNA glycosylase. It has a molecular weight of 30 000 and a Stokes radius of 26.4 A. The enzyme prefers double-stranded to single-stranded DNA and is stimulated by the presence of 0.1 M KCl in the reaction mixture.
一种能从DNA中切除带有碱开咪唑环（甲酰胺基嘧啶）的7-甲基鸟嘌呤的DNA糖基化酶已从大肠杆菌细胞提取物中纯化出来，纯化倍数超过8000倍。该酶不能从DNA中切割3-甲基腺嘌呤、尿嘧啶和完整的7-甲基鸟嘌呤。在含有嘧啶类似物如氧尿嘧啶、2,4,6-三氨基嘧啶、2,5,6-三氨基-2-羟基嘧啶硫酸盐、甲酰胺基嘧啶和5-亚硝基-2,4,6-三氨基嘧啶的测定中，只有两种化合物对该酶表现出终产物抑制作用。该酶被命名为甲酰胺基嘧啶-DNA糖基化酶。它的分子量为30000，斯托克斯半径为26.4埃。该酶更喜欢双链DNA而非单链DNA，并且反应混合物中0.1M KCl的存在会刺激其活性。
