花青素与小麦蛋白相互作用及对蛋白质结构的影响

利用荧光光谱法和傅里叶变换红外光谱法，研究中性条件下黑豆皮中的花青素（矢车菊素-3-O-葡糖苷（cyanidin-3-O-glucoside，C3G））与小麦蛋白麦醇溶蛋白（gliadin，Gli）及麦谷蛋白（glutenin，Glu）的相互作用。荧光结果表明：C3G对Gli、Glu均有较强的荧光猝灭作用，对Glu的荧光猝灭机制属于静态猝灭，而与Gli的猝灭方式为动态猝灭和静态猝灭的结合，C3G与Gli和Glu的结合常数（KA）分别为20.827×104、14.690×104 L/mol，结合位点（n）分别为1.263和1.159（298 K），说明与Gli作用较强。热力学研究表明：C3G与Gli主要通过疏水作用结合；与Glu作用主要通过范德华力和氢键作用结合。同步荧光光谱分析表明：C3G与Gli的结合位点更接近色氨酸残基，而与Glu的结合位点更接近酪氨酸残基。傅里叶变换红外光谱表明：C3G能够与Gli、Glu结合并相互作用，使蛋白构象发生变化。

WANG Chen,XIE Yanli,FAN Tingting

The interactions between cyanidin-3-O-glucoside (C3G) and wheat gluten (gliadin and glutenin) under neutral conditions were studied by fluorescence spectroscopy and Fourier transform infrared spectroscopy. The results showed that C3G had strong quenching effects on both proteins, and the fluorescence quenching mechanism of glutenin was static quenching, while the fluorescence of gliadin was quenched through the combination of dynamic quenching and static quenching mechanism. The binding constant (KA) and the number of binding sites (n) for the interaction between C3G and gliadin were larger, indicating stronger interaction with gliadin. Thermodynamic data indicated that the interaction between C3G and gliadin was mainly hydrophobic, while the interaction between C3G and glutein was mainly driven by van der Waals force and hydrogen bond. Synchronous fluorescence spectroscopy indicated that the binding site of C3G to gliadin was closer to the tryptophan residue, while the binding site of C3G to glutein was closer to the tyrosine residue. Fourier transform infrared spectroscopic data showed that C3G interacted with gliadin and glutein, altering the protein conformation.