In silico methods to identify ACE and DPP-IV inhibitory activities of ribosomal hazelnut proteins

In this study, an in silico attempt was made to evaluate the biological functionality of hazelnut (Corylus avellana L.) peptides, using three gastrointestinal (GI) and three non-GI enzymes. As of March 2017, 469 hazelnut proteins were listed on UniProt database. Here, a small subset (i.e., 23 ribosomal proteins) was investigated. Using in silico proteolysis, the efficacy of gastrointestinal proteases (i.e., trypsin, pepsin, chymotrypsin) were compared to various other non-GI proteases such as thermolysin, papain and bromelain for the generation of bioactive peptides. In most cases, gastrointestinal proteases (i.e., trypsin, pepsin, chymotrypsin) were shown to be less efficient compared to various other non-GI proteases such as thermolysin, papain and bromelain in the generation of bioactive peptides. After in silico proteolysis, the extent of angiotensin-converting enzyme (ACE)-inhibitory peptide content (A) accounted for approximately 5.1, 7.9 and 9.1% of all amino acids present for bromelain, thermolysin and papain treatments, respectively, while comparable results were obtained for dipeptidyl peptidase-IV (DPP-IV) inhibitory activity (4.8, 8, and 10.9%). In all cases, ACE- and DPP-IV inhibitory activities were dominant to all other activities. Based on the current findings, ribosomal hazelnut proteins could be considered as a valuable source of bioactive peptides.