Purification and Interaction of β-amylase from Dioscorea alata (Water Yam) with Epicatechin

Abstract

β-amylase is an enzyme that hydrolyzes the α-1,4-glucan bonds from the non-reducing ends of starch and other carbohydrate polymers reducing it to maltose units. Maltose has much application with food processing and pharmaceutical industries. The enzyme was purified to apparent homogeneity with a monomeric molecular weight of 30.1 kDa based on SDS-PAGE. The binding Constant (Ka), Kd ΔH, ΔS and ΔG values were 1.53103Lmol-1 ,3.12x10-4Lmol-1, 19.35kJmol-1, 56.67Jmol-1K-1, and -18.17kJmol-1 respectively. The binding profile of β-amylase with epicatechin was spontaneous with a stoichiometric ratio of 2:1. Hydrophobic bonding played a major role in stabilizing the β-amylase-ligand complex. The mode of reaction was by static quenching. It further dictates that the binding reaction is entropy driven. The inhibitory effect of this plant polyphenols on β-Amylase might contribute to the regulation of β-Amylase activity in plants.