title: Inactivation of Soybean Trypsin Inhibitor by Epigallocatechin Gallate: Stopped-Flow/Fluorescence, Thermodynamics, and Docking Studies.
abstract: Tea is one of the most widely daily consumed beverages all over the world, and it is usually consumed with milk and/or soy milk. However, very few researches have studied the interactions between tea polyphenols (TPs) and soy milk proteins as compared with milk proteins. Here, we reported that epigallocatechin gallate (EGCG), a major component of TPs, can effectively inhibit the inhibitory activity of Kunitz trypsin inhibitor (KTI, a major antinutrient in soy milk). The mechanism of inactivation of KTI by EGCG was investigated by stopped-flow/fluorescence, thermodynamics, and docking studies. The results indicated that EGCG binds KTI via both hydrophobic and hydrophilic interactions with an association constant of 6.62 × 105M-1to form a 1:1 complex. Molecular docking showed the participation of amino acids includes three amino acid residues (Asn13, Pro72, and Trp117) near the reactive site of KTI, which may prevent KTI from contacting trypsin and hence inactivate KTI.
authors.affiliation: Research and Development Center of Food Proteins, School of Food Science and Engineering, South China University of Technology , Guangzhou 510640, People's Republic of China.
authors.forename: Chun
authors.initials: C
authors.lastname: Liu
authors.affiliation: Research and Development Center of Food Proteins, School of Food Science and Engineering, South China University of Technology , Guangzhou 510640, People's Republic of China.
authors.forename: Fenfen
authors.initials: F
authors.lastname: Cheng
authors.affiliation: Research and Development Center of Food Proteins, School of Food Science and Engineering, South China University of Technology , Guangzhou 510640, People's Republic of China.|Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety, South China University of Technology , Guangzhou 510640, People's Republic of China.
authors.forename: Xiaoquan
authors.identifier: http://orcid.org/0000-0002-4016-9834
authors.initials: X
authors.lastname: Yang
mesh_terms: D020816:Amino Acid Motifs; D000818:Animals; D002392:Catechin / Q000031:analogs & derivatives* / Q000737:chemistry; D005453:Fluorescence; D007700:Kinetics; D008892:Milk / Q000737:chemistry; D062105:Molecular Docking Simulation; D041942:Soy Milk / Q000737:chemistry*; D013025:Glycine max / Q000737:chemistry; D013816:Thermodynamics; D014360:Trypsin Inhibitor, Kunitz Soybean / Q000737:chemistry*
chemical_list: D002392:Catechin; D014360:Trypsin Inhibitor, Kunitz Soybean; C045651:epigallocatechin gallate
keywords: EGCG; inactivation; interaction; molecular docking; soybean Kunitz trypsin inhibitor; spectroscopy