基于非共价键作用的山梨酸钾对植物蛋白荧光淬灭性能研究

Fluorescence Quenching Properties of Vegetable Protein Caused by Potassium Sorbate with Non-covalent Bonding Interactions

利用荧光光谱研究了在不同温度下,山梨酸钾(PSS)分别与大豆分离蛋白(SPI)和小麦面筋蛋白(WG)在溶液中的相互作用特性,探讨了山梨酸钾对这两种植物蛋白的荧光猝灭机理,测定了它们之间反应的表观结合常数及结合位点数。结果表明,山梨酸钾与两种植物蛋白之间分别生成了新的复合物,属于静态荧光淬灭。其中,山梨酸钾与SPI之间的相互作用在281 K、291 K和303 K时的表观结合常数分别为1.58×104L/mol、1.49×103L/mol和1.11×102L/mol,其对应的结合位点数分别为1.25、0.96和0.78,而山梨酸钾与WG之间的相互作用在281 K、291 K和303 K时的表观结合常数分别为2.90×104L/mol、2.53×104L/mol和5.50×104L/mol,其对应的结合位点数分别为1.04、1.06和1.15。热力学数据分析表明山梨酸钾与SPI反应作用力主要是范德华力和氢键作用,而与WG反应作用力主要是疏水作用力和电子作用力。

The interaction between potassium sorbate （PSS） and soy protein isolate （SPI） or wheat gluten （WG） under different temperatures in solution was investigated by fluorescence spectroscopy. The quenching mechanism was analyzed referring to PSS against the fluorescence of the vegetable protein. The apparent binding constants and the binding sites were also determined simultaneously based on the fluorescence. The experimental results clearly indicated that static quenching occurred in these systems because of the formation of new complexes among vegetable proteins and potassium sorbate. The apparent binding constants （KA） between PSS and SPI were 1.58×104 L/mol （281 K）, 1.49×103 L/mol （291 K）, and 1.11×102 L/mol （303 K）, respectively. The corresponding binding sites values （n） were 1.25, 0.96 and 0.78, respectively. The apparent binding constants between PSS and WG were 2.90×104 L/mol, 2.53×104 L/mol and 5.50×104 L/mol at 281 K, 291 K and 303 K, respectively. And the, corresponding binding sites values （n） were 1.04, 1.06 and 1.15, respectively. The changes of entropy and enthalpy indicated that the interaction of PSS and SPI was driven mainly by Vander waals force and hydrogen bonding, while the interaction of PSS and WG was chiefly driven by hydrophobic interaction and electronic force.