席夫碱大环铜配合物的化学核酸酶活性研究(英文)

Chemical Nuclease Activities of Schiff Base Macrocyclic Copper(Ⅱ) Complexes

对3种结构相近的席夫碱四氮大环草酰胺铜配合物(CuL1-3)的化学核酸酶活性进行比较研究。结果表明:这类配合物的化学核酸酶活性与中心金属离子的类型、配体的结构、溶液的pH值、离子强度及配合物的浓度等都有关系。3种配合物表现出来的化学核酸酶活性顺序为CuL3>CuL2>CuL1。CuL3的DNA切割反应表现为典型的假一级连续反应。在80μmol·L-1CuL3和2mmol·L-1H2O2的存在下,就超螺旋DNA向切口开环型DNA进而向线型DNA的转化而言,反应速率常数分别为0.0440±0.0015min-1(k1)和0.00352±0.00018min-1(k2)。

The chemical nuclease activities of three closely related Schiff base tetraazamacrocyclic oxamido copper（Ⅱ） complexes （CuL^1-3）were compared and the result shows that their chemical nuclease activities follow the order of CuL^3〉CuL^2〉CuL^1. Where complexes CuL^1-3 are [5,6-d] [ 13,14-d]dibenzo- 1,4,8,11 -tetraazacyclotetradeeane-dione-2,3-diene-7,11-di-ethylcarboxylate-7,12 Copper（Ⅱ）, [5,6-d][13,14-d]dibenzo-10-methyl-1,4,8,11-tetraazacyclo- tetradeeane-dione-2,3-diene-7,11-di-ethylearboxylate-7,12 Copper （Ⅱ） and [5,6-d] [13,14-d]dibenzo-[9,10-d] - cyclehexano-1,4,8,11-tetraazacyclotetradecane-dione-2,3-diene-7,11-di-ethylcarboxylate-7,12 Copper（Ⅱ）, respectively. The interactions of CuL^3 with DNA were studied in detail, and the results show that the chemical nuclease activity of this complex is affected by central metal ions, structure of ligands, pH value, ion strength and complex concentration. DNA cleavage reaction in presence of the copper （Ⅱ） complexes is a typical pesudo-first-order consecutive reaction, and the rate constants of 0.044 0±0.001 5 min^-1 （k1） and 0.003 52±0.000 18 min^-1 （k2） for the conversion of supercoiled to nicked DNA and nicked to linear DNA are obtained in presence of 80 μmol· L^-1 CuL^3 and 2 mmol· L^-1 H2O2, respectively.