黄酮“落新妇苷”与牛血清白蛋白相互作用研究

Study on the interaction between astilbin and bovine serum albumin

通过荧光法研究了落新妇苷与牛血清白蛋白(bovine serum albumin,BSA)之间的相互作用。考察了温度、BSA浓度、及常见离子对二者相互作用的影响。结果表明,落新妇苷具有较强的淬灭BSA内源荧光的能力,其淬灭机制为静态淬灭,表明二者可发生相互结合。计算了二者结合的热力学参数包括结合常数、焓变、熵变及自由能变化。结果表明,二者结合常数随温度的升高而缓慢增大,焓变及熵变均为正值说明疏水作用力在两者的相互作用中发挥重要的作用。Ca^(2+)、Mg^(2+)、K^+、SO_4^(2-)及NO_2^-等常见离子对落新妇苷与BSA相互作用的影响很小。同步荧光光谱研究表明落新妇苷会使BSA色氨酸残基附近疏水环境的极性增大。

The effects of temperature, BSA concentration and common ions on the interaction between astilbin and bovine serum albumin （BSA） were investigated by fluorescence method. The results showed that astilbin could quench the fluorescence of BSA through static quenching, which reflected the interaction between the two molecules. The thermodynamic parameters including binding constants, enthalpy change, entropy change and free energy change were calculated. The binding constant increased slowly with the increase of temperature, and the positive enthalpy and entropy change revealed that hydrophobic force played an important role in the interaction between the two molecules. Common ions, such as Ca 2＋ ,Mg 2＋ ,K ＋,SO 4 2- and NO - 2 had little effects on the interaction between astilbin and BSA. The results of synchronous fluorescence spectra showed that astilbin could increase the polarity of hydrophobic environment near the tryptophan residue of BSA.