CAJ | 학술논문

对2个4,4'-二甲基-2,2'-联吡啶锰(Ⅱ)配合物在生理条件及H2O2的存在下对DNA切割的动力学进行了研究.结果表明,这2个配合物分别存在下的DNA切割反应具有相似的动力学反应特征.其中对超螺旋DNA切割成缺口DNA步骤,均表现为三级反应,即反应速率分别与底物DNA的浓度、配合物的浓度和H2O2的浓度的一次方成正比;同时得到了2个反应的速率常数、活化能(Ea)、活化焓(△H≠)和活化熵(△S≠)等动力学参数,并根据这些结果提出了一个可能的氧化切割反应机理.
대2개4,4'-이갑기-2,2'-련필정맹(Ⅱ)배합물재생리조건급H2O2적존재하대DNA절할적동역학진행료연구.결과표명,저2개배합물분별존재하적DNA절할반응구유상사적동역학반응특정.기중대초라선DNA절할성결구DNA보취,균표현위삼급반응,즉반응속솔분별여저물DNA적농도、배합물적농도화H2O2적농도적일차방성정비;동시득도료2개반응적속솔상수、활화능(Ea)、활화함(△H≠)화활화적(△S≠)등동역학삼수,병근거저사결과제출료일개가능적양화절할반응궤리.
The kinetics of DNA cleavage, especially the conversion of supercoiled to nicked DNA, by two 4,4'- dimethyl-2,2'-pyridyl(dmbpy) manganese(Ⅱ) complexes, Mn(dmbpy)2(OCN)2(1) and Mn(dmbpy)2(dca)2(2), was investigated. Results show that there is similar kinetic characterization for complex 1-mediated DNA cleavage and 2- mediated DNA cleavage. For the conversion of supercoiled to nicked DNA, the overall reaction is three orders, i.e., the reaction rate is proportional to CDNA substrate, Ccomplexes and CH2O2, respectively. The rate constants are(2.54±0.36)×104 and (2.51±0.45)×104 L2·mol-2·s-1 at 37℃ for 1 and 2-mediated DNA cleavage, respectively. The temperature dependence of the rate constants results in the comparable activation energies(Ea), activation enthalpies(△H≠) and activation entropies (△S≠) for 1 and 2-mediated reactions, which suggests that the two reactions have similar organized transition states. Based on the above results, a mechanism for the Mn (Ⅱ) complexes-mediated DNA cleavage was proposed.