Investigating lignin from Canna edulis ker residues induced activation of α-amylase: Kinetics, interaction, and molecular docking

The lignin isolated from C. edulis ker residues showed a significant activating effect on α-amylase. Further studies revealed that the isolated lignin formed a 1:1 complex with α-amylase through hydrogen bonding and quenched fluorescence of α-amylase with a static quenching procedure. Binding with lignin led to conformational and granular size changes of α-amylase. Two-dimensional nuclear Overhauser spectroscopy (2D-NOESY) spectra suggested that OH in G units and β-O-4 structure were the major binding sites of lignin on the α-amylase molecule. Molecular docking studies indicated that the binding residue on α-amylase for lignin was not the same as for chloride ions, and the major binding force was hydrogen bonding. Furthermore, the docking results also showed the structural change of lignin induced by α-amylase. Thus, this work provided a new insight into the interaction between lignin from Canna edulis ker residues and α-amylase, which may be beneficial to apply lignin in the food industry.