Identification and Characterization of Novel Bioactive Peptide From Red Seaweed (Pyropia vietnamensis) Proteins

Pyropia vietnamensis is one of the most abundant seaweeds in the Indo-Pacific region. This study aimed to perform an in silico evaluation of P. vietnamensis proteins as potential precursors of bioactive peptides and to determine the novel peptide in terms of its half maximal inhibitory concentration (IC50) and the stability under controlled laboratory environment (in vitro) towards the dominant biological activity. The proteomic profiles of P. vietnamensis proteins were determined using LC-MS/MS analysis. Next, five proteins were chosen and employed for in silico analysis using the BIOPEP-UWM database. The in vitro characterizations of novel peptide were carried out using a dipeptidyl peptidase-IV (DPP-IV) inhibitor screening assay kit. In silico analysis revealed that DPP-IV and angiotensin-converting enzyme (ACE) inhibitors were the most potential bioactive peptides in P. vietnamensis proteins. Calpain 2, papain, pepsin (pH>2), and stem bromelain were predicted as the enzymes with the most potential to produce DPP-IV and ACE inhibitors. The novel peptides predicted were CFA, ACF, RFPS, DEWG, NYCL, CVPR, and DACF. The synthesized CVPR with an IC50 of 0.66 mg/ml exhibited stability at pH 3-7, 30-50 °C, and resisted gastrointestinal digestion. This study revealed P. vietnamensis proteins could offer health benefits due to the therapeutic potential with sustainable industrial applications on functional foods, nutraceuticals, and pharmaceuticals.