Abbreviations: ANS, 8-anilino-1-naphthalenesulphonic acid; BSA, bovine serum albumin; DPP-4, dipeptidyl peptidase-4; GIP, glucose-dependent insulinotropic polypeptide; GLP-1, glucagon-like peptide-1; GRAVY, grand average of hydropathicity; OPA, o-phthalaldehyde; pI, theoretical isoelectric point; RMSE, root mean square error; T2DM, type 2 diabetes mellitus; UPLC, ultra-performance liquid chromatography. AbstractIn silico and in vitro parameters were used to assess the potential of pigeon pea (Cajanus cajan) nutrient reservoir proteins as sources of dipeptidyl peptidase (DPP)-4 inhibitors. In silico, 40 pigeon pea proteins evaluated had 46% of amino acids associated with DPP-4 inhibition. After virtual hydrolysis, pepsin had the highest frequency of release and bioactivity of released DPP-4 inhibiting peptides, compared to papain and thermolysin. In vitro, thermolysin released the most active DPP-4 inhibitors.The protein hydrolysates contained similar amino acids but different particle sizes.Thus, the bioactivity patterns are attributable to the different nature and behavior of proteins/peptides under actual and virtual conditions. Using eight physicochemical variables, a random forest model with moderate prediction accuracy was developed for predicting DPP-4 inhibitory activity of papain hydrolysates. The findings demonstrate that proteins from pigeon pea are precursors of DPP-4 inhibitors, with potential use in formulating functional food for managing type 2 diabetes. | In silico analysis of physicochemical properties of pigeon pea proteinsPhysicochemical properties of the 40 mature pigeon pea proteins/ domains and BSA were calculated using the ProtParam feature of UniProtKB. The properties include the protein chain length, theoretical isoelectric point (pI), molecular weight, grand average of K E Y W O R D S bioactive peptides, bioinformatics, Cajanus cajan, dipeptidyl peptidase-4, in silico, pigeon pea S U PP O RTI N G I N FO R M ATI O N Additional supporting information may be found online in the Supporting Information section at the end of the article. How to cite this article: Boachie RT, Okoro FL, Imai K, et al. Enzymatic release of dipeptidyl peptidase-4 inhibitors (gliptins) from pigeon pea (Cajanus cajan) nutrient reservoir proteins: In silico and in vitro assessments. J Food Biochem.