• (−)-Epigallocatechin-3-gallate;
  • α-chymotrypsin;
  • docking;
  • green tea;
  • interaction;
  • spectroscopy;
  • trypsin


Tea polyphenol (TP) inhibits digestive enzymes and reduces food digestibility. To explore the interaction between TP with digestive enzymes, bindings of -epigallocatechin-3-gallate (EGCG) to trypsin and α-chymotrypsin were studied in detail using fluorescence, resonance light-scattering, circular dichroism, fourier transform infrared spectroscopy methods and protein-ligand docking. The binding parameters were calculated according to Stern–Volmer equation, and the thermodynamic parameters were determined by the van't Hoff equation. The results indicated that EGCG was capable of binding trypsin and α-chymotrypsin with high affinity, resulting in a change of native conformation of these enzymes. EGCG had a greater influence on the structure of α-chymotrypsin than trypsin. This study can be used to explain the binding interaction mechanism between TP and digestive enzymes.