Empirical and bioinformatic characterization of buffalo (Bubalus bubalis) colostrum whey peptides & their angiotensin I-converting enzyme inhibition

- Peptide library (<3 kDa) created for buffalo whey proteins.
- Peptides characterized after in vitro gastrointestinal digestion adopting nano-LC-MS/MS analysis.
- Whey proteins grouped into five functional gene clusters based on peptide sequences.
- Localization of whey proteins was proposed based on Yloc analysis.
- A lead octapeptide (m/z - 902.51, IQKVAGTW) synthesized inhibited ACE (IC50 300 µM) emulating standard drug lisinopril.

Whey based peptides are well known for their nutritional and multifunctional properties. In this context, whey proteins from buffalo colostrum & milk were digested by in vitro simulation digestion and analyzed by nano-LC-MS/MS. Functional protein association networks, gene annotations and localization of identified proteins were carried out. An ACE inhibitory peptide sorted from the library was custom synthesized and an in vitro ACE assay was performed. The study led to the identification of 74 small peptides which were clustered into 5 gene functional groups and majority of them were secretory proteins. Among the identified peptides, majority of them were found identical to angiotensin I-converting enzyme (ACE) inhibitors, antioxidant, antimicrobial, immunomodulatory and opioidal peptides. An octapeptide (m/z - 902.51, IQKVAGTW) synthesized was found to inhibit ACE with an IC50 of 300 ± 2 µM. The present investigation thus establishes newer vista for food derived peptides having ACE inhibitory potential for nutraceutical or therapeutic applications.