DNA BREAKAGE BY TANNIC-ACID AND CU(II) - SEQUENCE SPECIFICITY OF THE REACTION AND INVOLVEMENT OF ACTIVE OXYGEN SPECIES
DNA BREAKAGE BY TANNIC-ACID AND CU(II) - SEQUENCE SPECIFICITY OF THE REACTION AND INVOLVEMENT OF ACTIVE OXYGEN SPECIES
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DOI：
10.1016/0165-1161(94)90031-0
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发表时间：
1994-08-01
期刊：
影响因子：
--
通讯作者：
HADI, SM
中科院分区：
文献类型：
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作者：
BHAT, R;HADI, SM
单宁酸有许多化学、食品和药理学用途。在Cu（II）和分子氧的存在下，发现它会导致小牛胸腺DNA和超卷曲质粒DNA的断裂。用单宁酸处理lambda噬菌体DNA可以保护限制性内切酶DraI和EcoRI*的裂解，但对SmaI和HaeIII没有作用。结果表明，在所使用的条件下，单宁酸较好地结合AT碱基对。单宁酸- cu （II）处理生成的开放环状II型质粒DNA的限制性内切分析进一步表明，链断裂是在特定的位点或序列上引起的。在这个反应中，Cu(I)是一个必需的中间体，通过使用Cu(I)的隔离试剂neocuproine和bathocuproine。在没有DNA的情况下，一个单宁酸分子可以还原6个Cu（lI）离子。通过超氧化物歧化酶、硫脲、甘露醇、甲酸酯和过氧化氢酶对DNA断裂的抑制作用，确定了活性氧参与了反应。
Tannic acid has numerous chemical, food and pharmacological applications. In the presence of Cu(II) and molecular oxygen it was found to cause breakage of calf thymus DNA and supercoiled plasmid DNA. Treatment of lambda phage DNA with tannic acid protected cleavage with restriction endonucleases DraI and EcoRI* but not with SmaI and HaeIII. The results indicate that under the conditions used tannic acid preferably binds to AT base pairs. Restriction analysis of open circular form II plasmid DNA generated by tannic acid-Cu(II) treatment further showed that the strand breakage is caused at specific sites or sequences. In this reaction Cu(I) was shown to be an essential intermediate by using the Cu(I) sequestering reagents neocuproine and bathocuproine. By using job plots, we established that in the absence of DNA, six Cu(lI) ions can be reduced by one tannic acid molecule. The involvement of active oxygen species in the reaction was established by the inhibition of DNA breakage by superoxide dismutase, thiourea, mannitol, formate and catalase.