Abstract:The objective of this study was to investigate the porcine pancreatic α-amylase(PPA) inhibitory activity of glutenin and gliadin.The half maximal inhibitory concentration (IC50) was determined,and the kinetics of inhibition were investigated using Dixon and Cornish-Bowden plots.The results showed glutenin was mixed inhibitors with competitive and uncompetitive inhibitory impacts on α-amylase,while gliadin showed competitive inhibitory effects on α-amylase.The competitive inhibition constants (Kic) of glutenin and gliadin were (20.533±3.582),(49.619±5.949) mg/mL,respectively,and the uncompetitive inhibition constants (Kiu) of glutenin was (49.358±9.779) mg/mL.The IC50 values of glutenin and gliadin were (14.014±1.089) mg/mL and (33.193±0.621) mg/mL,respectively.For glutenin,the lower Kic vs.Kiu suggested that glutenin bound more tightly to free PPA than the PPA-starch complex.Compared with gliadin,glutenin displayed a stronger inhibitory effect on α-amylase.These results indicated that glutenin and gliadin may delay the digestion of starchy foods by inhibiting starch hydrolytic enzymes.And these results will enrich the mechanism of protein regulation of starch digestion.The findings are also of important practical value for the development of carbohydrate-restricted diet and protein-based functional foods.