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目的研究中药活性成分腺苷(adenosine,Ade)与人血清白蛋白(human serum albumin,HSA)的结合反应机制。方法利用荧光光谱及紫外吸收光谱实验测定了反应体系的结合常数K、结合位点数n,探讨了反应机制;依据Fōrster理论测定了反应体系的能量转移参数并考察了腺苷对人血清白蛋白构象的影响;分子模建腺苷与人血清白蛋白的结合反应模型并与实验结果进行了比较。结果腺苷与人血清白蛋白结合生成静态复合物,结合常数K=1.39×103L.mol-1,结合位点n=0.94;腺苷与人血清白蛋白的结合距离r很小,说明发生了能量转移现象;腺苷改变了人血清白蛋白结合位域的疏水性并造成微区构象发生变化。计算机模拟结果显示,腺苷与人血清白蛋白的相互作用主要为腺苷的嘌呤环与人血清白蛋白分子中氨基酸残基的疏水作用和氢键。结论理论计算与实验测试获得了一致性结果,此为中药活性成分腺苷的药理作用机制研究提供一定参考。
Objective To study the mechanism of the binding reaction between adenosine (Ade) and human serum albumin (HSA). Methods The binding constants K and binding sites n of the reaction system were determined by fluorescence spectroscopy and ultraviolet absorption spectroscopy. The reaction mechanism was discussed. The energy transfer parameters of the reaction system were determined by Fōrster theory and the effects of adenosine on the conformation of human serum albumin The molecular modeling of the binding reaction between adenosine and human serum albumin was compared with the experimental results. Results Adenosine combined with human serum albumin produced a static complex with a binding constant of K = 1.39 × 103 L · mol-1 and a binding site of n = 0.94. The binding distance between adenosine and human serum albumin was very small, Adenosine changes the hydrophobicity of the human serum albumin binding site and causes changes in the micro-conformation. Computer simulation results show that the interaction between adenosine and human serum albumin mainly adenosine and human serum albumin amino acid residues in the hydrophobic residues and hydrogen bonds. Conclusions The theoretical calculation and experimental tests have obtained the consistent results, which provide some references for the pharmacological mechanism of adenosine, the active ingredient of Chinese traditional medicine.