Breimer L H
Biochemistry. 1983 Aug 30;22(18):4192-7. doi: 10.1021/bi00287a005.
Urea-DNA glycosylase, an enzyme presumed to be active in the repair of DNA damage caused by oxidizing agents, has been identified previously in Escherichia coli. This enzyme has now been shown to be present in cell extracts of calf thymus and human fibroblasts. It catalyzes the release of free urea from a double-stranded polydeoxyribonucleotide containing thymine residues fragmented by KMnO4 and NaOH treatment. The calf thymus enzyme has been 400-fold purified and largely separated from previously identified mammalian DNA glycosylases. It has a molecular weight of about 25 000 and requires no cofactors. The identity of the enzymatically released product as unsubstituted urea has been verified by its susceptibility to urease.
尿素-DNA糖基化酶是一种推测在修复由氧化剂引起的DNA损伤中起作用的酶，此前已在大肠杆菌中被鉴定出来。现在已证明这种酶存在于小牛胸腺和人成纤维细胞的细胞提取物中。它催化从含有经高锰酸钾和氢氧化钠处理而断裂的胸腺嘧啶残基的双链多脱氧核糖核苷酸中释放出游离尿素。小牛胸腺酶已被纯化了400倍，并在很大程度上与先前鉴定的哺乳动物DNA糖基化酶分离开来。它的分子量约为25000，不需要辅因子。酶促释放产物为未取代尿素这一身份已通过其对脲酶的敏感性得到验证。
