Water-soluble vitamins for controlling starch digestion: Conformational scrambling and inhibition mechanism of human pancreatic α-amylase by ascorbic acid and folic acid.

Pallab Kumar Borah, Anwesha Sarkar, Raj Kumar Duary

Journal: Food chemistry 2019;288():395-404

PMID: 30902310

Full Text on Elsevier Science View on PubMed

Abstract

The inhibition of human pancreatic α-amylase (HPA) enzyme activity can offer facile routes to ameliorate postprandial hyperglycemia in diabetes via control of starch digestion. The present study utilizes complementary experimental (starch digestion kinetics, fluorescence quenching, Förster resonance energy transfer and X-ray diffraction) and computational (molecular docking and dynamics simulation) methods to evaluate the HPA inhibitory activity of eight water-soluble vitamins, for the first time. In particular, ascorbic acid inhibited HPA activity via non-competitive antagonism from two allosteric sites, by channeling the inhibition towards the active site cavity via the triose-phosphate isomerase (TIM) barrel. In contrast, folic acid inhibited HPA activity by binding competitively to the active site cavity and decreasing the disorder in the neighboring loops 3 and 7, which are important mobile loops in HPA for starch digestion. The infusion of such biocompatible and nutritional water-soluble vitamins alongside starch may offer new avenues for diabetes management.

Address: Department of Food Engineering and Technology, School of Engineering, Tezpur University, 784 028, India; Food Colloids and Processing Group, School of Food Science and Nutrition, University of Leeds, LS2 9JT, United Kingdom. Electronic address: [email protected].; Food Colloids and Processing Group, School of Food Science and Nutrition, University of Leeds, LS2 9JT, United Kingdom. Electronic address: [email protected].; Department of Food Engineering and Technology, School of Engineering, Tezpur University, 784 028, India. Electronic address: [email protected].

DOI: 10.1016/j.foodchem.2019.03.022

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MeSH Terms: Ascorbic Acid, Binding Sites, Catalytic Domain, Fluorescence Resonance Energy Transfer, Folic Acid, Humans, Kinetics, Molecular Docking Simulation, Pancreas, Pancreatic alpha-Amylases, Starch, Vitamins