Evidence for two DNA repair enzymes for 8-hydroxyguanine (7,8-dihydro-8-oxoguanine) in human cells.
Evidence for two DNA repair enzymes for 8-hydroxyguanine (7,8-dihydro-8-oxoguanine) in human cells.
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DOI：
10.1016/s0021-9258(19)36531-7
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发表时间：
1993-09
期刊：
影响因子：
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通讯作者：
T. Bessho;K. Tano;H. Kasai;E. Ohtsuka;S. Nishimura
中科院分区：
文献类型：
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作者：
T. Bessho;K. Tano;H. Kasai;E. Ohtsuka;S. Nishimura
8-羟基鸟嘌呤（也称为7，8-二氢-8-氧代鸟嘌呤; OH 8 Gua，oxo 8 Gua）的两种DNA修复酶已在人HeLa细胞核提取物中鉴定。一种是OH 8 Gua-糖基化酶，另一种是缺乏OH 8 Gua-糖基化酶活性的OH 8 Gua-内切核酸酶。它们通过肝素-琼脂糖柱色谱分离，并通过内切酶切口测定或通过使用高压液相色谱-电化学检测器测量从底物DNA释放的OH 8 Gua来表征。两种OH 8 Gua修复酶均仅作用于含有OH 8 Gua/C、OH 8 Gua/T或OH 8 Gua/G的双链体底物DNA的含OH 8 Gua链。含有OH 8 Gua/A碱基对的DNA是两种酶的非常差的底物。OH 8 Gua-内切核酸酶同时切割OH 8 Gua残基两侧的磷酸二酯键，留下5 ′-羟基和3 ′-羟基。
Two DNA repair enzymes for 8-hydroxyguanine (also known as 7,8-dihydro-8-oxoguanine; OH8Gua, oxo8Gua) have been identified in human HeLa cell nuclear extract. One is OH8Gua-glycosylase and the other is OH8Gua-endonuclease that lacks OH8Gua-glycosylase activity. They were separated by heparin-Sepharose column chromatography and characterized by endonuclease nicking assay or by measuring the OH8Gua released from substrate DNA using high pressure liquid chromatography-electrochemical detection. Both OH8Gua repair enzymes act only on the OH8Gua-containing strand of the duplex substrate DNA containing OH8Gua/C, OH8Gua/T, or OH8Gua/G. DNA containing OH8Gua/A base pair was very poor substrate for either enzymes. OH8Gua-endonuclease simultaneously cleaves phosphodiester bonds on both sides of the OH8Gua residue, leaving 5‘-hydroxy and 3‘-hydroxy groups.