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采用内源荧光光谱、圆二色光谱以及分子模拟表征了大豆皂苷Ⅱ与牛血清白蛋白(BSA)之间的相互作用.内源荧光光谱显示,大豆皂苷Ⅱ使BSA最大发射波长略微蓝移且出现荧光猝灭,色氨酸残基的微环境疏水性增加,蛋白质分子构象发生改变;大豆皂苷Ⅱ也使BSA的圆二色光谱负椭圆率下降,肽链伸展,改变了BSA的二级结构.计算机模拟分子对接显示了两者稳定的结合,大豆皂苷Ⅱ的阿拉伯糖基及鼠李糖基与BSA形成氢键作用,参与其中的重要氨基酸有Asp108、Asp111、Arg144和Arg458,皂苷的三萜烯部分则伸进由15个氨基酸残基构成的疏水腔中形成疏水相互作用.“,”Intrinsic fluorescence spectrometry,circular dichroism spectrometry and molecular modeling methods were used to investigate the interaction between soyasaponin Ⅱ and bovine serum albumin (BSA).Results showed that the adding of soyasaponin Ⅱ caused the fluorescence quenching and a decrease of the maximum emission wavelength,leading to the increase of hydrophobicity around tryptophan and the change of tertiary structure of BSA.The binding of soyasaponin Ⅱ also reduced the negative ellipticity of circular dichroism spectra,unfolded the peptide chain and changed the secondary structure of BSA.Molecular docking revealed a good binding of soyasaponin Ⅱ to BSA,with arabinopyranosyl and rhamnopyranosyl parts of the sugar chain forming hydrogen bonds with Asp l08,Asp111,Argl44 and Arg458,and the aglycone moiety interacting with 15 amino acids by hydrophobic interaction.