经典铂抗癌药物的作用机理可根据其对肿瘤细胞DNA的双齿、双功能作用导致DNA的复制受阻来解释.最近又发现一类新的具有通式cis-[Pt(NH_3)_2(N-het)Cl]Cl(N-het是类吡啶芳香氮碱配体)的化合物具有良好的抗癌活性,但对这类抗癌药物提出了两种可能的作用机理.一种是先脱去1分子氨,然后在体内产生活性体cis-[Pt(NH_3)(N-het)]^(2+),另一种是单功能键合到 DNA上而 N-het作为一个插入基团起作用.然而,最新的实验事实排除了第一种机理,而第二种键合和插入机理又未被实验所证实.因此,研究三元配合物M(UTP)(N-bet)^(2-)分子内芳环间堆积作用有可能对这种机理提供有用的信息.本文用pH电位滴定法研究了三元Zn(UTP)L^(2-)配合物(UTP^(4-)-5’-三磷酸尿苷,L-苯并咪唑(Bi)或异喹啉(Iq))的稳定性,与咪唑(Im)相关三元配合物稳定性比较并结合~1H NMR研究结果,表明在所研究的三元配合物分子中存在着明显的芳环堆积作用.1材料与方法5’-三磷酸尿苷三钠盐(Na_2HUTP·2H_2O)购自美国Serva高级化学公司,其他试剂见参考文献[3,4] .用配有Russell CE 711/LF复合电极的Orion SA 720型pH计(美国)测定溶液的pH值.实验条件见参考文献[4].在测定三元配合物[Zn^(2+)]-[UTP^(4-)]稳定常数时,由于Zn(UTP)^(2-)配合物稳定性高,故在实?
The i nteraction among Co(phen) 33+ ,6-Mercaptopurine(6-MP)and calf thymus DNA has been investigated us-ing c yclic voltammetry,differential pulse voltammetry and UV-spectra in Tris buffer solutions(pH=7.2).In the presence of6-MP,the redox peak current at0.15V for the central cobalt ion from voltammograms is significantly reduced compared with th at in the absence of6-MP and the current of a new quasi-reversible redox wave shown at-0.06V gradually increases with6-MP addition.However,when DNA is furthe r added,the peak current at0.15V is renewedly enlarged and the redox at-0.06V gr adually disappears with DNA addition.At the same time,UV-spectra of Co(phen) 33+ are regularly changed in the presence of6-MP and DNA.All results indicate t hat the obvious interaction equilibrium is proved to exist among Co(phen) 33+ ,6-MP and calf thymus DNA.
