Interactions between α-amylase and an acidic branched polysaccharide from green tea.

Interactions between α-amylase and an acidic branched polysaccharide from green tea.
Int J Biol Macromol. 2016 Oct 15;:
Authors: Wu S, Lai M, Luo J, Pan J, Zhang LM, Yang L
Abstract
To understand the mechanism responsible for the α-amylase inhibitory activity of tea polysaccharides, the interaction between α-amylase and an acidic branched tea polysaccharide (TPSA) was investigated using fluorescence spectroscopy and resonance light scattering analysis. TPSA, exhibiting inhibitory activity towards α-amylase (the maximum inhibition percentage of 65%), was isolated from green tea (Camellia sinensis) and characterized by nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, and gas chromatography. Synchronous fluorescence spectroscopy revealed that the binding interaction between the tryptophan residues of α-amylase and TPSA was predominant. Based on the fluorescence quenching effect of tryptophan residues induced by TPSA, the binding constants between α-amylase and TPSA were determined to be 18.6×10(6), 8.0×10(6) and 4.6×10(6) L·mol(-1) at 20, 30 and 37°C, respectively. The calculated Gibbs free-energy changes were negative, indicating that the bonding interaction was a spontaneous process. The enthalpy and the entropy changes were -62.13 KJ·mol(-1) and -0.0728 KJ·mol(-1)·K(-1), suggesting that hydrogen bonding interactions might play a major role in the binding...

Source: International Journal of Biological Macromolecules - October 14, 2016 Category: Biochemistry Authors: Wu S, Lai M, Luo J, Pan J, Zhang LM, Yang L Tags: Int J Biol Macromol Source Type: research