光谱法结合分子对接的甲苯磺丁脲与乳清蛋白的相互作用研究

目的 在生理条件下使用紫外光谱法、荧光光谱法以及分子对接研究甲苯磺丁脲与乳清蛋白的相互作用。方法 实验选取激发波长280 nm，测定不同温度下甲苯磺丁脲与乳清蛋白的荧光猝灭光谱；通过相关参数（结合常数、结合位点数等）的计算以及热力学参数判断猝灭机制、甲苯磺丁脲与乳清蛋白的相互作用特点以及乳清蛋白构象的变化，并通过分子对接方法探究药物与乳清蛋白之间可能存在的作用形式。结果 甲苯磺丁脲可使乳清蛋白内源荧光发生作用机制为复合式静态猝灭的猝灭；以氢键、范德华力为主要作用力类型；甲苯磺丁脲与乳清蛋白结合过程中存在非辐射能量转移，促使乳清蛋白的荧光猝灭；药物与蛋白的结合对乳清蛋白的构象无明显影响；分子对接结果表明：甲苯磺丁脲分别与Glu113残基形成1个氢键，与Asp116残基形成2个氢键以及与Glu121残基形成2个氢键。结论 甲苯磺丁脲与乳清蛋白可以发生相互作用，因此建议甲苯磺丁脲不要和牛奶同服。

Study on interaction between tolbutamide and lactalbumin by spectroscopy and molecular docking

Objective To study the interaction between tolbutamide and lactalbumin under physiological conditions via fluorescence spectroscopy, ultraviolet spectroscopy and molecular docking. Methods The excitation wavelength of 280 nm was selected to measure the fluorescence quenching spectra at different temperatures. The quenching mechanism, the interaction characteristics between drug and lactalbumin, and the changes in the conformation of lactalbumin were determined by calculating related parameters (binding constant, number of binding sites, etc.) and thermodynamic parameters. The possible forms of interaction between drug and lactalbumin were explored by molecular docking method. Results Tolbutamide can cause lactalbumin endogenous fluorescence to occur by quenching by composite static quenching; the main force types are hydrogen bond and van der Waals force; It was inferred that non-radiative energy transfer occurred during the binding of tolbutamide to lactalbumin, which promoted the quenching of lactalbumin. Synchronous fluorescence spectroscopy, ultraviolet absorption spectroscopy and three-dimensional fluorescence spectra showed that the binding reaction had no obvious effect on the conformation of lactalbumin. The molecular docking results showed that tolbutamide formed one hydrogen bond with Glu113 residue, two hydrogen bonds with Asp116 residue and two hydrogen bonds with Glu121 residue. Conclusion Tolbutamide can spontaneously interact with lactalbumin. It is suggested that tolbutamide should not be taken with milk.