光谱法研究对氨基苯乙酮缩对二甲氨基苯甲酰腙与DNA的相互作用

Spectroscopic studies of interaction between p-aminoacetophenone-p'-dimethylaminobenzoyl hydrazone and DNA

合成了对氨基苯乙酮缩对二甲氨基苯甲酰腙(AAPABH),采用荧光光谱法和UV-Vis吸收光谱法研究了AAPABH与DNA的相互作用。在pH 7.4Tris-HCl缓冲溶液中,以345 nm激发该化合物发射弱荧光,加入DNA后出现明显的荧光增强现象,表明探针分子与DNA结合形成了稳定配合物,其结合常数为5.48×107L/mol。研究了离子强度对体系荧光强度的影响,结果显示NaCl的加入未引起AAPABH-DNA体系荧光强度明显变化,表明AAPABH和DNA间不存在静电作用;同时DNA对AAPABH吸收光谱的影响表现为减色效应、探针分子与热变性后的DNA作用力明显小于与未变性DNA间的作用力、探针分子与溴化乙锭(EB)竞争结合DNA使得EB-DNA体系荧光猝灭,上述实验结果均表明探针分子主要以嵌插作用方式与DNA作用。

A new compound,p-amino-acetophenone-p-dimethylamino benzoyl hydrazone（AAPABH） was synthesized and used as a fluorescent probe sensing for DNA.A significant increase in the fluorescence intensity of AAPABH was observed upon addition of ct-DNA in pH 7.4 Tris-HCl buffer solution when excited at 345 nm.This suggested that a stable complex between AAPABH and DNA was formed and the binding constant was estimated as 5.48×107 mol/L.The results of the competitive experiment of the probe with ethidium bromide（EB） to bind DNA,absorption spectral change upon addition of DNA,and the different intensity change degree of the probe in the presence DNA or denatured DNA revealed that the interaction between the probe and DNA was via intercalation.Scatchard plots also confirmed the binding model.Additionally,ionic strength experimental result showed the electrostatic interaction was very weak.