分子光谱法研究恩替卡韦和牛血清白蛋白之间的相互作用

Interaction between Entecavir and Bovine Serum Albumin by Molecular Spectroscopy

利用分子光谱技术研究了恩替卡韦和牛血清白蛋白(BSA)之间的相互作用.恩替卡韦对牛血清白蛋白荧光的猝灭机制属于静态猝灭.在25,35和45℃下,恩替卡韦和牛血清白蛋白之间的结合常数分别为9.13×103,7.96×103,5.46×102L/mol,相应的结合位点数n分别为0.781,0.780,0.751.三个温度下的热力学参数变化值(ΔH,ΔG和ΔS)以及园二色谱的研究表明:结合反应的主要作用力类型为疏水作用力,熵变化驱动该结合反应而焓变化不利于该结合反应.根据Forster非辐射能量转移理论,测得恩替卡韦与BSA之间的结合距离为2.7 nm.根据同步荧光光谱证明牛血清白蛋白与恩替卡韦结合位点接近牛血清白蛋白的Thr色氨酸残基.

Spectroscopic techniques were employed to investigate the interaction between entecavir and bovine serum albumin（BSA）. The results indicate that the quenching mechanism of BSA by entecavir is a static quenching process. The apparent binding constants,Ka and the binding sites values, n between entecavir and BSA are 9. 13 × 10^3L/mol, 0. 781 （25 ℃）, 7.96× 10^3L/mol, 0. 780 （35 ℃） and 5. 46× 10^3L/mol, 0. 751 （45℃）, respectively. The thermodynamic parameters, △H,△G and △S, calculated at different temperatures and the results of circular dichroism （CD） indicate that hydrophobic force plays a major role in the interaction of entecavir with BSA. The positive enthalpy （△H） and entropy （△S） values of the interaction of entecavir and BSA indicate that the binding reaction is mainly entropy-driven with an unfavorable enthalp . Based on the Forster＇s theory of non-radiation energy transfer, the binding distance, r,between the donor （BSA） and acceptor （entecavir） is evaluated to be 2. 7 nm at 25 ℃. The binding site of entecavir with BSA was found to be approaching the microenvironment of Thr by the synchronous fluorescence spectrometry.