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目的采用荧光光谱法研究灯盏花素与牛血清白蛋白(BSA)在生理条件下(pH 7.4)的相互作用机制。方法固定BSA浓度,依次加入不同浓度的灯盏花素溶液,在激发波长为280 nm下,290~500 nm的波长范围内进行荧光猝灭光谱、同步荧光光谱扫描。结果灯盏花素对BSA的荧光猝灭类型是静态猝灭;在温度288 K和310 K时,二者的结合常数KA分别为8.295×105和3.302×105L.mol 1;二者的结合位点数n分别为1.239 3和1.177 0。由热力学参数焓变(H=31.080kJ.mol 1)小于零和熵变(S=5.392 J.mol 1.K 1)大于零,确定灯盏花素与BSA之间的作用力类型为静电作用力;生成自由能变(G)为负值,表明灯盏花素与BSA的作用过程是一个自发过程。此外,应用同步荧光光谱考察了灯盏花素对BSA构象的影响。结论经过荧光光谱分析,可以确定灯盏花素与白蛋白的作用机制,为其开发成治疗心血管疾病新药提供理论依据。
Objective To study the interaction mechanism between breviscapine and bovine serum albumin (BSA) under physiological conditions (pH 7.4) by fluorescence spectroscopy. Methods The concentration of BSA was fixed, and different concentrations of breviscapine solution were added in sequence, and the fluorescence quenching spectra and synchronous fluorescence spectra were scanned in the wavelength range of 290 ~ 500 nm at the excitation wavelength of 280 nm. Results Breviscapine quenched the fluorescence quenching of BSA. At temperatures of 288 K and 310 K, the binding constants KA of breviscapine were 8.295 × 105 and 3.302 × 105 L · mol 1, respectively. The binding sites of the two n are 1.239 3 and 1.177 0, respectively. From the thermodynamic parameters enthalpy change (H = 31.080kJ.mol 1) is less than zero and entropy change (S = 5.392Jmol 1.K 1) is greater than zero, to determine the type of force between breviscapine and BSA electrostatic force (G) is negative, indicating that the interaction between breviscapine and BSA is a spontaneous process. In addition, the effect of breviscapine on the conformation of BSA was investigated by synchronous fluorescence spectroscopy. Conclusion Fluorescence spectrum analysis can determine the mechanism of breviscapine and albumin and provide a theoretical basis for its development into a new drug for the treatment of cardiovascular diseases.