Mechanism of curcumin-induced trypsin inhibition: Computational and experimental studies

• Binding interaction of curcumin with trypsin was investigated.
• There was the one main binding site of trypsin for curcumin.
• Curcumin affected the activity of trypsin by entering into the primary substrate-binding pocket.
• Docking results explain the binding behavior and preference of binding site.

In the present study, the experimental and theoretical methods were used to analyze the binding interaction of food dye, curcumin with trypsin. The results of fluorescence spectroscopic measurements indicated that curcumin binding resulted in the obviously intrinsic fluorescence quenching with the increase concentration of curcumin. This binding interaction is a spontaneous process with the estimated enthalpy and entropy changes being −15.70 kJ mol−1 and 40.25 J mol−1 K−1, respectively. Hydrogen bonds and hydrophobic forces played an important role in the complex formation between curcumin and trypsin. Moreover, curcumin could enter into the primary substrate-binding pocket and makes the activity of trypsin decrease remarkably with the increasing concentration of curcumin.