Abstract: In order to investigate the effects of tea polyphenols on the conformation and antigenicity of αs1-casein, epigallocatechin gallate (EGCG) and epigallocatechin (EGC), tea polyphenols with high bioactivity, were used for grafting onto αs1-casein. The conformational changes of αs1-casein were studied by fluorescence, synchronous fluorescence and circular dichroism (CD) spectroscopy, and the changes in the antigenicity of αs1-casein were analyzed by indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) and Western blot assay. The results showed that EGC and EGCG both quenched the fluorescence of αs1-casein, and affected the Tyr and Trp residues of αs1-casein. The α-helix and β-sheet contents of αs1-casein increased slightly, and the random coil content decreased slightly. The conformational change of αs1-casein resulted in a significant decrease in the antigenicity of αs1-casein. The effect of EGCG on the conformation and antigenicity of αs1-casein was stronger than that of EGC.

Key words: αs1-casein; epigallocatechin gallate; epigallocatechin; conformation; antigenicity

摘要： 为探明茶多酚对αs1-酪蛋白构象和抗原性的影响，选用茶多酚中活性较强的表没食子儿茶素没食子酸酯 （epigallocatechin gallate，EGCG）和表没食子儿茶素（epigallocatechin，EGC）接枝αs1-酪蛋白。通过荧光光谱、 同步荧光光谱和圆二色谱研究αs1-酪蛋白构象变化，通过间接竞争酶联免疫方法、免疫印迹实验分析αs1-酪蛋白抗原 性变化。结果表明：EGC、EGCG均对αs1-酪蛋白内部荧光有猝灭作用，对αs1-酪蛋白的酪氨酸（tyrosine，Tyr）和 色氨酸（tryptophan，Trp）残基均有影响，αs1-酪蛋白的α-螺旋和β-折叠含量略有增加，无规卷曲含量略有降低； αs1-酪蛋白构象的变化导致其抗原性显著降低，EGCG对αs1-酪蛋白构象和抗原性的影响显著强于EGC。

关键词: αs1-酪蛋白；表没食子儿茶素没食子酸酯；表没食子儿茶素；构象；抗原性