Studies On The Interaction Of Copper-Complexes With DNA And Electrochemically Induced DNA Cleavage

Since the cantineoplastic activity of cis-[Pt(NH₃)₂Cl₂] complex was discovered, the studies on the interaction of small molecules with DNA are attracting great interest in the field of molecular biochemistry. The studies on interaction models and mechanism of metal complexes with DNA are very important in the fields of cantineoplastic pharmaceuticals, molecular biochemistry and bioengineering technology. Based on the interaction of metal complexes with DNA, DNA cleavage by appropriate methods is important to acquire the formation of DNA sequence and prohibit the replication of cancer gene. In this thesis, the research includes two parts. In the first part, the interaction of coordination compounds of copper with DNA was studied by electrochemistry and spectroscopy method. In the second part, the ability to cleavage DNA of several Cu(â…¡) complexes was researched by electrochemistry and chromatography method. Copper is recognized as an essential metal element widely distributed in the biological system. The interaction of copper-bipyridyl (Cu(bpy)₂²⁺) complex with DNA was investigated by voltammetry, absorption and fluorescence spectrophotometry. The mechanism of Cu(bpy)₂²⁺ complex with DNA was studied also. Based on the interaction of metal complexes with DNA, several copper complexes, such as Cu(bpy)₂²⁺ ,Cu(ssal)₂²⁺ (copper-sulfosalicylic acid complex), were choose as electronic transfer media to induce DNA cleavage by Electrochemical method. The influence of several experimental conditions including electrode potential, electrolysis time and the concentration of complexes on DNA cleavage was studied in detail. And oxygen is required for electrochemically induced DNA cleavage. The cleaved DNA fragments were separated and detected by high performance liquid chromatography (HPLC). In the basis of experiment results, the mechanism of DNA cleavage by electrochemically induced metal complexes was discussed. This method of DNA cleavage which reaction condition was tender and similar to physiological condition is beneficial to further develop the new technique of DNA cleavage. The electrochemically method can modulate redox reaction, and it can perform the redox reaction on the electrode without addition of extra reductants and oxidants.