pH值对大豆11S球蛋白结构和表面疏水性的影响

采用Lowry法、8-苯氨基萘-1-磺酸铵盐（8-anilinonaphthalene-1-sulfonic acid ammonium salt，ANS）荧光探针法研究pH值对大豆11S球蛋白的溶解性和表面疏水性的影响，并利用圆二色光谱和荧光光谱对不同pH值条件下11S球蛋白二级结构和三级结构进行分析，为研究大豆蛋白结构与表面疏水性之间的构效关系提供理论基础。结果表明：除等电点外，大豆11S球蛋白溶解性和表面疏水性呈负相关，并且随着pH值的升高，大豆球蛋白二级结构中发生β-折叠和无规卷曲向α-螺旋的转变，三级结构中色氨酸（Trp）残基微环境极性降低。大豆球蛋白的表面疏水性与α-螺旋结构含量呈负相关。

Influence of pH on Structure and Surface Hydrophobicity of Glycinin

Lowry method, 8-anilinonaphthalene-1-sulfonic acid ammonium salt (ANS) fluorescence probe, circular
dichroism and fluorescence spectroscopy were applied to explore the solubility, surface hydrophobicity, secondary structure
and tertiary structure of glycinin at different pH conditions with the aim to provide the theoretical basis for the research on
relationship between soybean protein structure and surface hydrophobicity. The results showed that the transformation from
β-sheet structure and random coil to α-helix structure occurred, and the microenvironment polarity of Trp residues revealed
an obvious decrease with increasing pH. A negatively linear correlation between the surface hydrophobicity and solubility
of glycinin was observed, and the surface hydrophobicity of glycinin was also negatively correlated with the content of
α-helix structure.