两种方法研究新型光敏剂五聚赖氨酸-2-羰基酞菁锌与牛血清白蛋白相互作用

目的研究新型光敏剂五聚赖氨酸-2-羰基酞菁锌（ZnPc-（Lys）5）与牛血清白蛋白（BSA）之间的相互作用。方法从BSA角度采用荧光光谱法和紫外可见光谱法通过荧光猝灭实验探讨ZnPc-（Lys）5与BSA相互作用的猝灭机制、结合常数及结合位点;从ZnPc-（Lys）5角度采用胶束荧光增敏法测定ZnPc-（Lys）5浓度通过Scatchard方程计算ZnPc-（Lys）5与BSA相互作用的结合常数和结合位点数。结果荧光猝灭实验结果表明ZnPc-（Lys）5对BSA的荧光有强烈的猝灭作用,猝灭机制主要是静态猝灭形成基态配合物。不同温度（298,303,308,313,318 K）的结合常数K1分别为12.1×104L/mol,7.69×104L/mol,6.12×104L/mol,4.57×104L/mol,3.76×104L/mol,结合位点数分别为0.93,1.02,1.07,1.13,1.17。Scatchard方程计算出298 K结合常数K2为1.557×105L/mol,结合位点数位1.07。结论从两个方面计算的结合常数和结合位点数基本一致,ZnPc-（Lys）5与血清白蛋白之间主要通过形成基态配合物的方式相互作用,进入血清白蛋白中1个结合位点。

Interaction of Pentalysine β-carbonyl-phthalocyanine Zinc with Bovine Serum Albumin: Two Methods

Objective To investigate the interaction of pentalysine β-carbonyl-phthalocyanine zinc（ZnPc-（Lys）5） with bovine serum albumin（BSA） by two methods.Methods From the point of BSA,the quenching mechanism,binding constants and sites of the interaction between ZnPc-（Lys）5 and BSA was investigated through the fluorescence quenching experiment by fluorescence spectrometry and UV-visible spectroscopy.From the point of ZnPc-（Lys）5,the constants and sites of the interaction were calculated through micellar enhanced spectrofluorometric determination of ZnPc-（Lys）5 concentration with Scatchard equation.Results The mechanism of fluorescence quenching is static quenching process.The binding constants and the number of binding sites were calculated at different temperatures（298,303,308,313,318 K）： 12.1,7.69,6.12,4.57,3.76×104 L/mol and 0.93,1.02,1.07,1.13,1.17,respectively.The binding constant and the number of binding sites calculated from Scatchard equation at 298 K were 1.557×105 L/mol and 1.07,respectively.Conclusion The two methods produce approximately identical data of the binding constant and sites.The results indicate that ZnPc-（Lys）5 strongly binds to BSA at a molar ratio of 1∶1.