Identification of Peptide Based Inhibitors for α-Amylase by Phage Display

Type II diabetes mellitus has been a global health problem with adverse side effects if left untreated. Recent studies have shown the inhibition of α-Amylase in degrading dietary starch is able to reduce postprandial hyperglycaemia in diabetic patients. Developments of specific inhibitors for α-Amylase thus provide an attractive alternative for the management of diabetes. Inhibiton of α-Amylase may be achieved by promoting inhibitor complexation by induced fit binding for enzyme inactivation. Peptides that are capable of mimicking or block the active sites would be idle inhibitors. Here, we employed peptide phage display to obtain a bioactive substitute capable of inhibiting α-Amylase activity. After three rounds of biopanning against α-Amylase using a 20-mer random peptide library, enrichment of target specific peptide pools were analyzed. Enriched pool of phage peptides were further used to screen for monoclones that are specific to α-Amylase. Two peptides, FAPMTSVMQSWWDVWRGGS (G5) and CLAEFTLWDRFWFGGRSGGR (G6) were identified from DNA sequencing. These two peptides at phage level exhibited approximately 18 % inhibition of α-Amylase activity. Purified G5 peptide was showed approximately 50 % inhibition for both Bacillus sp. and porcine pancreatic α-Amylase, but purified G6 peptide only presented approximately 40 % inhibition of Bacillus sp. α-Amylase. The use of phage display to identify peptides, which mimic the ‘natural’ motifs that contribute to the enzyme activity of α-Amylase may be a promising approach for management of diabetes.