亚甲基蓝与鲱鱼精DNA相互作用的光谱法研究

Spectroscopy Studies of Interaction between Methylene Blue and Herring Sperm DNA

以吖啶橙(AO)作为光谱探针,采用UV和荧光光谱等方法研究了亚甲基蓝(MB)与鲱鱼精DNA的作用机制.确定了在低浓度MB时,MB与DNA以嵌插方式作用;而在高浓度MB时,MB与DNA之间为混合作用方式.结合比n(MB)∶n(DNA)=10∶1,结合常数K26℃=2.46×105L·mol-1,MB-DNA复合物的表观摩尔吸光系数ε=5.70×106L·mol-1·cm-1.同时研究了酸度和温度等对MB与DNA相互作用的影响,热力学研究推导了MB结合DNA为焓驱动反应.

The UV-VIS spectroscopy and fluorescence spectroscopy were applied to investigate the mechanism of the interaction between methylene blue （MB） and herring sperm DNA by using acridine orange as a spectral probe in Tris-HCl buffer （pH 7.0）. The chief action mode was comfirmed to be an intercalation binding at a lower MB concentration but the mixed action modes at a higher concentration. Combining ratio of the binary complex is n（MB） ： n（DNA）=10 ： 1, the binding constant of MB with DNA is K260℃^-=2.46×10^5L·mol^-1 and the apparent molor absorptivity is ε=5.70×10^6L·mol^-1·cm^-1. Meanwhile, the interaction of MB with DNA was effected by the changes of pH and temperature. The results deduce that the interaction between MB and DNA is an enthalpy driven reaction.