2 DISTINCT HUMAN DNA DIESTERASES THAT HYDROLYZE 3'-BLOCKING DEOXYRIBOSE FRAGMENTS FROM OXIDIZED DNA
2 DISTINCT HUMAN DNA DIESTERASES THAT HYDROLYZE 3'-BLOCKING DEOXYRIBOSE FRAGMENTS FROM OXIDIZED DNA
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DOI：
10.1093/nar/19.21.5907
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发表时间：
1991-11-11
影响因子：
14.9
通讯作者：
DEMPLE, B
中科院分区：
文献类型：
--
作者：
CHEN, DS;HERMAN, T;DEMPLE, B
研究了哺乳动物细胞中有助于纠正DNA氧化损伤的酶。我们专注于3‘-修复二酯酶，它通过去除阻止DNA修复合成的3’阻断脱氧核糖片段来处理氧化链断裂的DNA末端。在多种小鼠、牛和人的组织和培养细胞中发现了两种酶。这两种活性从HeLa细胞中得到不同程度的纯化。一种酶具有已知的HeLa AP内切酶（M(r)约38,000）的特性，具有相同的底物特异性和。反应要求，以及与抗hela AP内切酶抗血清的交叉反应性)，并被认为与该蛋白相同。第二种活性不与抗hela AP内切酶抗体相互作用，AP内切酶活性相对较低。这第二种酶可能已经在其他研究中检测到，但从未表征过。除了3'-修复二酯酶和AP内切酶外，这种部分纯化的制剂还具有DNA 3'-磷酸酶和3'-脱氧核糖二酯酶的活性。目前尚不清楚在第二种制备中检测到的所有活性是否都是由于单个蛋白质，尽管没有检测到对未受损DNA的活性。这两种广泛分布的3'-修复二酯酶/AP内切酶在体内的作用尚未确定，但随着本文的描述，这些问题现在可能会得到关注。
Mammalian cells were investigated for enzymes that help correct oxidative damages in DNA. We focused on 3'-repair diesterases, which process DNA ends at oxidative strand breaks by removing 3'-blocking fragments of deoxyribose that prevent DNA repair synthesis. Two enzymes were found in a variety of mouse, bovine and human tissues and cultured cells. The two activities were purified to differing degrees from HeLa cells. One enzyme had the properties of the known HeLa AP endonuclease (M(r) approximately 38,000, with identical substrate specificity and. reaction requirements, and cross-reactivity with anti-HeLa AP endonuclease antiserum) and is presumed identical to that protein. The second activity did not interact with anti-HeLa AP endonuclease antibodies and had relatively less AP endonuclease activity. This second enzyme may have been detected in other studies but never characterized. In addition to the 3'-repair diesterase and AP endonuclease, this partially purified preparation also harbored DNA 3'-phosphatase and 3'-deoxyribose diesterase activities. It is unknown whether all activities detected in the second preparation are due to a single protein, although activity against undamaged DNA was not detected. The in vivo roles of these two widely distributed 3'-repair diesterase/AP endonucleases have not been determined, but with the characterizations presented here such questions may now be focused.