以人血清白蛋白(HSA)为实验材料,通过荧光光谱、等温滴定量热及紫外-可见吸收光谱等技术研究化疗药物紫杉醇与其的结合机理.荧光光谱检测结果表明:紫杉醇主要通过氢键和范德华力与HSA结合,并引起其内源荧光的猝灭.在温度为303k下,二者间的结合常数为10.7x103 l/MOl.紫外-可见吸收光谱检测发现,随着紫杉醇浓度的增加,HSA在278nM处的吸收峰增大,证明二者结合后HSA的构象发生了改变.等温滴定量热实验则进一步说明二者的结合是一个自发进行的放热反应,在温度为303k下结合常数为8.8x103 l/MOl,焓变、熵变及吉布斯自由能分别为-99.1kJ/MOl,-183.6J/(MOl·k)和-43.5kJ/MOl.本研究为紫杉醇在血液中的运输及传递提供理论支持.The interaction mechanism of chemotherapy drugs paclitaxel with human serum albumin(HSA)was studied using fluorescence spectroscopy,isothermal titration calorimetry,and UV spectroscopy.The result of fluorescence experiment showed that the intrinsic fluorescence of HSA was quenched by the binding of paclitaxel,with an binding constant of 10.7×103 L/mol at 303K,and the main forces were hydrogen bonds and van der Waals forces.The result of UV-visible spectroscopy experiment showed that the absorption peak of HSA at 278nm increased with the increase of concentrations of paclitaxel.Such phenomenon implied that the interaction might lead to the conformation change of HSA.Isothermal titration calorimetry experiment further confirmed that the interaction between HSA and paclitaxel is a spontaneous process of exothermic reaction,of which the binding constant,enthalpy change,entropy,and Gibbs free energy are 8.8×103 L/mol,-9.9kJ/mol,-183.6J/(mol·K)and-19.1kJ/mol,respectively at 303K.Our current study provides a theoretical explanation for processes of transport and delivery of paclitaxel in the blood.中央高校基本科研业务费专项资金项
