盐酸多赛平与牛血清白蛋白结合反应光谱法研究

SPECTROMETRIC STUDY ON THE INTERACTION BETWEEN DOXEPIN HYDROCHLORIDE AND BOVINE SERUM ALBUMIN

用荧光法和紫外-可见光谱法研究了在生理条件下,盐酸多赛平(DH)和牛血清白蛋白(BSA)结合反应的特征。实验发现DH对BSA的荧光有较强猝灭作用,DH的紫外吸收光谱和BSA的荧光光谱有一定程度的重叠现象,20℃反应的结合常数为4.42×104mol/L,DH在BSA分子上色氨酸残基所在区域的结合位点数为1.75,结合反应的标准焓变、标准熵变、标准吉布斯自由能分别为-15.16kJ/mol、36.83J/(mol.K)、-25.95kJ/mol,作用距离r=3.70nm。

The interaction between doxepin hydrochloride （DH） and bovine serum albumin （BSA） in physiological conditions was studied by fluorescence and UV - absorption spectrometry. The results showed that DH had ability to quench the BSA fluorescenee via non - radiation energy transfer mechanism. The fluorescence quenching data was analyzed according to Stern - Volmer equation and double - reciprocal equation. At the temperrature of 20 ℃, the thermodynamic parameters of binding reaction were determined as follows： the molar change of enthalpy, the molar change of entropy and the molar change of gibbs energy were 15.16 kJ/mol, 36.83 J/（ mol · K）, and 25.95 kJ/mol, respectively. The binding constant was found to be 4.42 × 10^4 mol/L, the binding number of DH on the vicinity of tryptophane residue of BSA was determined to be 1.75 and the binding distance to be 3.70 nm.