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 (Ka) of 2.19 × 103 M-1 and 0.25 × 103 M-1 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.
Keywords: (−)-Epigallocatechin (EGC) (PubChem CID: 72277); (−)-Epigallocatechin gallate (EGCG) (PubChem CID: 65064); Acetic acid (PubChem CID: 176); Dimethyl sulfoxide (DMSO) (PubChem CID: 679); EGCG; Inactivation; Interaction mechanism; Molecular docking; Nα-benzoyl-dl-arginine 4-nitroanilide hydrochloride (BAPNA) (PubChem CID: 2724371); Potassium bromide (PubChem CID: 253877); Soybean Bowman-Birk trypsin inhibitor.
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