中文摘要：

运用圆二色光谱（CD）和荧光光谱法（FS）,探讨茶叶儿茶素（EGCG）对胰脂肪酶（PPL）二级和三级结构的变化规律;同时,以橄榄油为底物,研究反应时间和EGCG浓度对胰脂肪酶活性的影响。结果表明：EGCG对PPL的抑制作用1h后达到最大值,抑制率为30%。EGCG低浓度（≤1mmol/L）时,EGCG对PPL的抑制率随EGCG浓度升高而增大,当EGCG超过此浓度时,抑制率随EGCG浓度的升高基本保持不变。Lineweaver-Burk作图可知,EGCG对PPL的抑制类型为非竞争性抑制作用。CD和FS分析表明,EGCG对PPL二级和三级结构均有一定的影响,PPL二级结构的变化与EGCG浓度呈正相关,而三级结构的变化与EGCG浓度没有显著的相关性。FS图谱还表明,EGCG对PPL色氨酸存在荧光淬灭现象,且静态淬灭和动态淬灭同时存在。

英文摘要：

The effect of（–）-epigallocatechin-3-gallate（EGCG） on the structure-activity relationship of pancreatic lipase was studied in this work.The secondary and tertiary structures of pancreatic lipase were measured by circular dichroism（CD） and fluorescence spectroscopes（FS）,respectively.Using olive oil as the substrate,the activity of pancreatic lipase as a function of incubation time and EGCG concentration was also investigated.The results showed that the maximum inhibitory rate was observed after 1 h mixing of EGCG with pancreatic lipase.The inhibitory rate rapidly increased with increasing EGCG concentration up to 1 mmol/L and then remained basically unchanged as the EGCG concentration continued to increase.The Lineweaver-Burk plot showed that EGCG non-competitively inhibited the activity of pancreatic lipase.CD and FS analyses suggested that EGCG influenced both the secondary and tertiary structures of pancreatic lipase,and its concentraiton was positively correlated with the secondary structure but had no significant correlation with the tertiary structure.FS analyses also indicated that EGCG quenched the Trp fluorescence of pancreatic lipase statically or dynamically.