Assessment of the DPP-IV inhibitory potential of mung bean and adzuki bean protein hydrolysates using enzymatic hydrolysis process: specificity of peptidases and novel peptides

Mung bean and adzuki bean protein concentrates were hydrolysed to the same degree of hydrolysis by two peptidases: Flavourzyme and Alcalase. Peptide fractions were analysed using MALDI-TOF MS to investigate the differences in enzyme cleavage specificity and the inhibition activity of Dipeptidyl peptidase-IV (DPP-IV), using bioinformatics tools. It was shown that each peptidase showed specific selectivity in cleaving the designated substrate at a specific site. Alcalase main cutting sites on mung bean and adzuki bean proteins were identified as hydrophobic amino acid residues, particularly between Leu-X (X-Leu) or Phe-X (X-Phe) while Flavourzyme cleavage occurred between peptide bonds between Gln-X (X-Gln) or Pro-X (X-Pro). The findings demonstrated that Flavourzyme had a higher capacity for generating active peptides from both mung bean and adzuki bean protein concentrates with higher levels of DPP-IV inhibitory activity. Proteomics and bioinformatics methodologies provided the essential knowledge required to explore novel peptides with DPP-IV inhibitor potential from mung bean and adzuki bean hydrolysates.