Multiple Bioactivities of Peptides from Hydrolyzed Misgurnus anguillicaudatus

Abstract

Misgurnus anguillicaudatus (loach) is a widely distributed benthic fish in Asia. In this study, the alkaline protease was used to hydrolyze loach, and the hydrolysate products of different molecular weights were obtained by membrane separation. In vitro antioxidant assays showed that the <3 kDa fraction (SLH-1) exhibited the strongest antioxidant activity (DPPH, hydroxyl radical and superoxide radical scavenging ability, and reducing power), while SLH-1 was purified by gel filtration chromatography, and peptide sequences were identified by LC-MS/MS. A total of six peptides with antioxidant activity were identified, namely SERDPSNIKWGDAGAQ (D-1), TVDGPSGKLWR (D-2), NDHFVKL (D-3), AFRVPTP (D-4), DAGAGIAL (D-5), and VSVVDLTVR (D-6). In vitro angiotensin-converting enzyme (ACE) inhibition assay and pancreatic cholesterol esterase (CE) inhibition assay, peptide D-4 (IC50 95.07 μg/mL, 0.12 mM) and D-2 inhibited ACE, and peptide D-2 (IC50 3.19 mg/mL, 2.62 mM), D-3, and D-6 acted as pancreatic CE inhibitors. The inhibitory mechanisms of these peptides were investigated by molecular docking. The results showed that the peptides acted by binding to the key amino acids of the catalytic domain of enzymes. These results could provide the basis for the nutritional value and promote the type of healthy products from hydrolyzed loach.

Novel Angiotensin-Converting Enzyme-Inhibitory Peptides Obtained from Trichiurus lepturus: Preparation, Identification and Potential Antihypertensive Mechanism

“…Among the identified peptides, FAGDDAPRR, QGPIGPR, and GPTGPAGP exhibited notable antioxidant activity and ro- Analysis of binding sites between ACE and peptides and inhibition kinetics would lead to a better understanding of the modes of activity of peptides [40][41][42]. In addition, the C-terminal amino acid of peptides could affect their ACE-inhibitory activity significantly, and the hydrophobicity and three-dimensional structure of the C-terminal amino acids are crucial factors for their ACE-inhibitory activity [13,41,43]. Moreover, gastrointestinal digestion results could determine whether peptides are affected by enzymes of the gastrointestinal tract [44][45][46].…”

“…ACE-inhibitory activity was assessed by following the experimental procedure reported by Dou et al [13], with slight modifications. A solution of borate-buffered HEPES (50 mM, pH 8.3) was dispensed into a 96-well plate, followed by the addition of samples (100 µL), ACE (50 µL, 0.1 U/mL, prepared from 50 mM borate buffer pH 8.3), and FAPGG(N-[3-(2-Furyl)acryloyl]-Phe-Gly-Gly) (50 µL, 1 mM) into each well.…”

The transcriptome sequencing analysis reveals immune mechanisms of soybean fermented powder on the loach (Misgurnus anguillicaudatus) in response to Lipopolysaccharide (LPS) infection

“…In traditional Chinese medicine, because of its nutritional and medicinal value, the loach is often called 'Ginseng water' (6). Furthermore, the loach is widely distributed in low-lying rivers in Asia (7,8) and has become a traditional and popular food in East Asian countries such as China and Korea (8)(9)(10)(11). The loach can smartly and flexibly inhabit the bottom mud and survive under extreme conditions such as rising water temperature and arid environments (12,13), but diseases caused by microbial infection and other environmental factors have threatened the healthy growth of the loach (14,15).…”