光谱及等温滴定量热法探究盐酸阿霉素与DNA作用机理

利用荧光光谱法，紫外可见光谱法，红外光谱法，圆二色谱法和等温滴定量热法等手段，对抗癌药物盐酸阿霉素 (DOX) 与DNA的作用过程进行研究，测得了它们的结合常数K_a、结合位点数n、反应焓变ΔH、熵变ΔS及ΔG，且在结合过程中，B型DNA的螺旋结构在一定程度发生改变。荧光光谱的数据显示出显著的猝灭效应, 表明DNA是一个DOX荧光的很好的猝灭剂。红外光谱表明阳离子DOX+通过静电吸引与 DNA 的磷酸基团相互作用，且DOX的碳氢链通过疏水缔合与DNA作用。ITC测定了DOX和DNA相互作用的焓变和熵变，表明DOX的烃链和DNA的碱基之间的疏水性相互作用提供了结合的驱动力。

Exploration of the Interaction Mechanism between Doxorubicin Hydrochloride and DNA by Spectroscopic Techniques and Isothermal Titration Calorimetry

The interaction processing of anti-cancer drug doxorubicin hydrochloride (DOX) with DNA was systematically investigated using fluorescence spectroscopy, ultraviolet-visible spectroscopy, infrared spectroscopy，circular dichroism and isothermal titration calorimetry measurements. The binding constant Ka, the binding-site number n, the reaction enthalpy ΔH and the reaction entropy ΔS of the interaction were obtained. In the binding process, the helix of B-DNA can have a certain degree of structural variations. The data of fluorescence spectrum indicated that DNA was a good quencher for the fluorescence of DOX. IR data certified the cation DOX+ binding with the phosphate groups of DNA through strong electrostatic attraction, while the C-H bonds of DOX may be associated with the bases of DNA by hydrophobic interaction. The Changes of enthalpy and entropy of the binding process were determined by ITC, which indicated that the process was driven by the hydrophobic interactions between the hydrocarbon chain of DOX and the bases of DNA.