Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency, School of Pharmaceutical Science and Technology, Tianjin University, Tianjin 300072, PR China.
State Laboratory of Food Nutrition and Safety, Tianjin University of Science and Technology, Tianjin 300457, PR China.
Food Chem. 2020 Jan 15;303:125380. doi: 10.1016/j.foodchem.2019.125380. Epub 2019 Aug 19.
Soybean Bowman-Birk trypsin inhibitor (BBTI), an antinutritional factor of soy products, could strongly inhibit the protein digestion. The inactivation effect and mechanism of BBTI induced by tea polyphenols (TPs) and its major components (EGCG and EGC), were investigated in this study using fluorescence, FTIR, CD spectroscopy, isothermal titration calorimetry (ITC) and molecular docking. EGCG and EGC interacted with BBTI via static quenching process and hydrophobic interaction, with binding constant (K) of 2.19 × 10 M and 0.25 × 10 M at 298 K, respectively. TPs, EGCG and EGC induced a transition of BBTI conformation from disorder to order. ITC analysis and molecular docking revealed the interaction of EGCG-BBTI and EGC-BBTI were spontaneous, and hydrophobic interactions and hydrogen bonds were the predominant forces. Overall, this study clearly suggested that EGCG could be a promising inactivating agent for BBTI, which could also improve the safety and nutritional value of soy products.
大豆 Bowman-Birk 胰蛋白酶抑制剂（BBTI）是大豆制品中的一种抗营养因子，能强烈抑制蛋白质的消化。本研究采用荧光、FTIR、CD 光谱、等温滴定量热法（ITC）和分子对接技术，研究了茶多酚（TPs）及其主要成分（EGCG 和 EGC）对 BBTI 的失活作用及其机制。EGCG 和 EGC 通过静态猝灭过程和疏水相互作用与 BBTI 相互作用，在 298 K 时的结合常数（K）分别为 2.19×10⁻⁴M 和 0.25×10⁻⁴M。TPs、EGCG 和 EGC 诱导 BBTI 构象从无规卷曲向有序转变。ITC 分析和分子对接表明，EGCG-BBTI 和 EGC-BBTI 的相互作用是自发的，疏水相互作用和氢键是主要作用力。总的来说，这项研究清楚地表明，EGCG 可能是 BBTI 的一种有前途的失活剂，这也可以提高大豆制品的安全性和营养价值。
