Effect of α-glucosidase inhibitor on human pancreatic and salivary α-amylase

Abstract

The mode of inhibition of a new complex oligosaccharide that inhibits the α-glucoside hydrolase activity of pancreatic and salivary α-amylase was studied. Kinetic analysis revealed a non-competitive type of inhibition with a K i of 1.47 ± 0.03 μg when tested against human pancreatic α-amylase and 3.89 ± 0.08 μg against human salivary α-amylase. The inhibitory action of α-glucoside hydrolase inhibitor (α-GHI) on pancreatic amylase was observed over a wide range of pH (6.0–7.9), whereas the inhibition of salivary amylase was optimal at pH 6.5. Column chromatographic investigations suggested the possible formation of an enzyme-inhibitor complex because the mixture of α-GHI and pancreatic α-amylase was eluted as a single component through a Sephadex G 200 column. However, this enzyme-inhibitor complex was easily separated into each component and the enzyme activity was fully recovered after electrophoresis.