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制备了５′端共价连接ＥＤＴＡ的寡聚核苷酸与生命金属的螯合物ＯＤＮ－５′－ＥＤＴＡＭ（ｎ＋），其中Ｍ（ｎ＋）为Ｆｅ（Ⅱ），Ｃｏ（Ⅱ）或Ｃｕ（Ⅱ）；分析、计算了这３个螯合物形成的最佳ｐＨ值范围，ＯＤＮ－ＥＤＴＡＦｅ（Ⅱ）为ｐＨ５．８～８．６，ＯＤＮ－ＥＤＴＡＣｏ（Ⅱ）为ＰＨ４．６～８．１，ＯＤＮ－ＥＤＴＡＣｕ（Ⅱ）为ｐＨ３．４～５．７；在此条件下，剪切反应必须的Ｍｇ２＋并不与Ｆｅ（Ⅱ），Ｃｏ（Ⅱ）或Ｃｕ（Ⅱ）竞争ＥＤＴＡ，也不会形成沉淀；讨论了ＯＤＮ－ＥＤＴＡＭ（ｎ＋）切割ＤＮＡ双链的反应机理：修饰寡核苷酸通过氢键在ＤＮＡ双链的大沟结合形成三链体，在Ｏ２和还原剂ＤＴＴ作用下，Ｆｅ作为催化剂，产生羟基自由基，氧化糖环，切割ＥＤＴＡＦｅ（Ⅱ）附近的ＤＮＡ双链．
The chelate ODN-5’-EDTAM (n +), which is a 5 ’end covalently attached to the oligonucleotide of EDTA and living metal, was prepared in which M (n +) was Fe (Ⅱ), Co Ⅱ). The optimum pH range for the formation of these three chelates was calculated and analyzed. The ODN-EDTAFe (Ⅱ) was pH5.8 ~ 8.6 and the ODN-EDTACo (Ⅱ) , ODN-EDTACu (Ⅱ) is pH3.4-5.7. Under these conditions, Mg2 + necessary for the cleavage reaction does not compete with Fe (Ⅱ), Co (Ⅱ) or Cu (Ⅱ) The formation mechanism of ODN-EDTAM (n +) cleavage of DNA double strand was discussed. The modified oligonucleotide formed triplex by the hydrogen bond in the major groove of DNA double strand. Under the action of O2 and reducing agent DTT, Fe As a catalyst, a hydroxyl radical is generated, the sugar ring is oxidized, and the DNA double strand in the vicinity of EDTAFe (II) is cleaved.