Lignin binding to pancreatic lipase and its influence on enzymatic activity

In this paper, we find that the effect of lignin on pancreatic lipase (PL) is dependent on reaction medium and substrate used. Experimental results reveal that lignin can gradually bind to PL to form a PL–lignin complex, resulting in an increased activity of the enzyme. The binding process is spontaneous and the PL–lignin complex formation is an endothermic reaction induced by hydrophobic and electrostatic interaction. There is a non-radiation energy transfer from PL to lignin during the binding process, and the binding of lignin to PL conforms to a secondary exponential decay function. Moreover, the α-helix content of the enzyme will be changed and the rigidity of its side chain will be enhanced due to the formation of lignin–PL complex. This study has not only provided the activation effect of lignin on PL, but also given an insight into the interaction between lignin and the enzyme, which would benefit the application of lignin in the pharmacy and food industry, as well as other fields.