Recent researches highlighted proteins from silkworm cocoons as sources of bioactive peptides with potential applications in therapy and health promotion. Meanwhile, multifunctional peptides are increasingly recognized as better candidates for health improvement and disease prevention in contrast to single-function peptides. Hence, this in silico study was conducted to identify potential multifunctional peptides from silkworm cocoons. Eight major proteins of the silkworm cocoons were subjected to in silico hydrolysis by 33 enzymes on the BIOPEP-UWM web server. Focusing on the active fragments with anti-angiotensin I-converting enzyme (ACE), anti-dipeptidyl peptidase IV (DPP-IV), anti-renin and antioxidant activities, we obtained a collection of more than 30,000 bioactive peptides. Among the 33 enzymes, calpain 2 released the largest number of bioactive peptides (5026 peptides). Further grouping based on functionality revealed a prominent group consisting of 1927 dual-function ACE and DPP-IV inhibitory peptides. Screening of the bifunctional peptides for non-toxicity, non-allergenicity, gastrointestinal digestion tolerance and high gastrointestinal absorption gave rise to four dipeptides, namely AF (Ala-Phe), IL (Ile-Leu), PG (Pro-Gly) and AG (Ala-Gly). Molecular docking and binding mode analyses suggest that the dipeptides could be non-competitive ACE inhibitors and competitive DPP-IV inhibitors. Overall, our study highlights silkworm cocoon proteins as a promising source of multifunctional peptides with health-promoting potential.
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