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投稿时间：2019-02-10
投稿时间：2019-02-10
中文摘要: 探究表没食子儿茶素没食子酸酯（epigallocatechin gallate，EGCG）与乳清分离蛋白（whey protein isolate，WPI）间的相互作用。测定不同pH 值与不同离子浓度条件下WPI 的紫外吸收光谱、导数光谱和荧光光谱，利用Stern-Volmer 方程判断荧光猝灭机制，采用位点结合模型公式计算结合常数和结合位点数。结果表明，紫外吸收光谱和导数光谱结果显示EGCG 改变了WPI 中酪氨酸和色氨酸残基所处的微环境，使WPI 的分子构象发生了变化。荧光光谱结果显示EGCG 可以有规律地猝灭WPI 的内源荧光，猝灭机理为静态猝灭，EGCG 与WPI 结合常数在pH 2.0～9.0 范围内随pH 的增大先减小后增大，在离子浓度0.10 mol/L～0.20 mol/L 范围内随离子浓度的增大而增大，结合位点数约为1。EGCG 与WPI 间存在静电相互作用。
中文关键词: 表没食子儿茶素没食子酸酯 乳清蛋白 导数光谱 荧光光谱 相互作用
Abstract:The interaction between epigallocatechin gallate （EGCG）and whey protein isolate （WPI）were studied.The UV absorption spectra，derivative spectra and fluorescence spectra of WPI at different pH and ion concentration were measured.The fluorescence quenching mechanism was determined by Stern -Volmer equation.The binding constants and the number of binding sites were calculated by the site binding model formula.UV absorption spectra and derivative spectra showed that EGCG changed the microenvironment of tyrosine and tryptophan residues in WPI and altered the molecular conformation of WPI.The fluorescence spectra showed that EGCG could regularly quench the intrinsic fluorescence of WPI.The quenching mechanism was static quenching.The binding constant of EGCG and WPI decreased first and then increased with the increase of pH value in the range of 2.0-9.0，and increased with the increase of ion concentration in the range of 0.10 mol/L-0.20 mol/L，and the number of binding sites was about 1.The above results indicated that there was an electrostatic interaction between EGCG and WPI.
keywords: epigallocatechin gallate whey protein isolate derivative spectrum fluorescence spectrum interaction
文章编号：202001002 中图分类号： 文献标志码：
基金项目:国家自然科学基金地区项目（31860474）；云南省教育厅科学研究基金重点项目（2019J0117）；云南省科技计划项目重点项目（2016FA014）
| Author Name | Affiliation |
| WU Yun-xue，LI Juan，GAO Qing，DONG Wen-ming，HE Jin-song | College of Food Science and Technology，Yunnan Agricultural University，Kunming 650201，Yunnan，China |
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