In Silico and In Vitro Assessment of Portuguese Oyster (Crassostrea angulata) Proteins as Precursor of Bioactive Peptides (original) (raw)
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Proteins from fresh New Zealand green-lipped mussels were hydrolyzed for 240 min using pepsin and alcalase. The extent of the hydrolysis, antioxidant, antimicrobial, and angiotensin-converting enzyme (ACE) inhibitory activities of each protein hydrolysate were investigated. Peptides obtained from pepsin hydrolysis after 30 min, named GPH, exhibited the highest antioxidant and ACE inhibitory activity, but no antimicrobial activity. Purification of the GPH using gel-filtration chromatography revealed that the protein fraction (GPH-IV*) containing peptides with a molecular weight (MW) below 5 kDa had the strongest antioxidant and ACE inhibitory activities. Further purification was done using reverse-phase HPLC (RP-HPLC) and the only major peak obtained (GPH-IV*-P2) had the highest antioxidant and ACE inhibitory activity. From this fraction, several bioactive peptides with an MW ≈ 5 kDa were identified using LC-MS and in silico analyses. This research highlights that green-lipped mussel...
Biomedicine & Preventive Nutrition, 2014
The antioxidant and anticancer activities of bioactive peptide isolated from oyster (Saccostrea cucullata) protein hydrolysate were evaluated in vitro. The oyster hydrolysate exhibited a strong antioxidant potential as a DPPH scavenger (85.7 ± 0.37%) followed by reducing power (2.63 ± 0.2 OD at 700 nm) at a concentration of 1 mg/ml. Due to the high antioxidant potential, hydrolysate was fractionated in Sephadex G-25 gel filtration chromatography and peptides were purified by UPLC-MS. Among 7 purified peptides (SCAP1-7), 3 peptides (SCAP1, 3 and 7) had the highest scavenging ability on DPPH radicals. The amino acid sequence and molecular mass of purified peptides (SCAP1, SCAP3 and SCAP7) were Leu-Ala-Asn-Ala-Lys (MW = 515.29 Da), Pro-Ser-Leu-Val-Gly-Arg-Pro-Pro-Val-Gly-Lys-Leu-Thr-Leu (MW = 1432.89 Da) and Val-Lys-Val-Leu-Leu-Glu-His-Pro-Val-Leu (MW = 1145.75 Da), respectively. Moreover, oyster peptide SCAP1 had anticancer activity against human colon carcinoma (HT-29) cell lines. Percentage of cell growth inhibition (MTT assay), apoptotic morphological changes (AO/EtBr staining) and oxidative DNA damage (comet assay) were estimated. We thus conclude that the anticancer and antioxidative peptide (SCAP1) from oyster (S. cucullata) may be useful ingredients in pharmaceutical and nutraceutical applications.
Heterogeneity of Proteinase Inhibitors in the Water-Soluble Organic Matrix from the Oyster Nacre
Marine Biotechnology, 2007
We extracted proteinase inhibitors from the nacre of the oyster Pinctada margaritifera with water. Mixing the nacre powder with water for 20 h led to a water-soluble fraction [0.24% (wt/wt) of nacre]. After dialysis of the water-soluble matrix through 6-to 8-kDa and 0.5-kDa membranes, the proteinase inhibitors were divided into low and high molecular weight fractions that contained inhibitors of papain, bovine cathepsin B, and human cathepsin L. We studied the heterogeneity of the inhibitors after separating the low molecular weight fraction according to charge and hydrophobicity. After multistep purification, mass spectrometry analysis revealed that a potent inhibitory fraction contained several molecules. This observation demonstrates the difficulties encountered in attempting to isolate individual metabolites from the complex mixture of molecules present in nacre matrix. Interestingly, the low molecular weight fraction contained specific inhibitors that could discern between cathepsin B and cathepsin L. The nacre organic inhibitors were active against several cysteine proteinases, yet they were more specific in relation to serine proteinases, because only proteinase K was inhibited. These results demonstrate, for the first time, the presence of active proteinase inhibitors in the mollusc shell, and it is possible that these inhibitors may play a role in either protection of proteins involved in shell formation or in defense against parasites, or both.
Food Chemistry, 2022
This study aimed to investigate the effect of steam cooking on the proteolysis of Pacific oysters (Crassostrea gigas) using the simulated oral-gastrointestinal digestion model and a NCM460 cell monolayer. Steam cooking changed the peptide profile of the digests of oysters considerably and induced more thorough hydrolysis. However, the heat-stable allergen, Cra g 1, still had remnant fragments in the intestinal phase, which could be allergenic epitopes. Two regions of Cra g 1 (residues 224-228 and 245-248) were digestion-tolerant. Furthermore, more oligopeptides were derived from raw proteins than from steamed proteins. After molecular docking and in vitro determination, six novel angiotensin I-converting enzyme inhibitory (ACEi) peptides were finally identified in the hydrolysates (WIS, WLS, LSL, SGPF, LGPI, and IGLP). Among them, LSL exhibited the highest ACEi activity (IC50 = 107.17 nM). Our findings provide supportive information on the effective utilization of oyster proteins.
2013
To manipulate enzymatic hydrolysis of tilapia (Oreochromis niloticus) muscle protein for production of bioactive peptides, its reaction kinetics was intensively studied. The study showed that the production of peptides with different bioactive properties including antioxidant activity, angiotensin-I-converting enzyme (ACE) inhibition and Ca-binding property and their kinetics were affected by the degree of hydrolysis and substrate concentration. A comparative study on reaction kinetics found that the kinetic parameters for the production of each bioactive peptide are unique, that is, the maximum initial velocity, V max , for hydrolysis of protein was as high as 1.07 mg mL À1 min À1 , but that for the production of peptides with antioxidant activity and Ca-binding property were very low, range of 7.14-66.7 lg mL À1 min À1 , and that for the production of peptides with ACE inhibitory activity was the lowest, at 2.57 lg mL À1 min À1. This knowledge of reaction kinetics of protein hydrolysis would be useful for manipulating and optimising the production of peptides with desired bioactive properties.
Journal of Applied Phycology, 2013
Isolation of bioactive compounds and commercialization of marine microalgae sources are interesting targets in future marine biotechnology. Cultured biomass of the marine microalga, Nannochloropsis oculata, was used to purify angiotensin-I converting enzyme (ACE) inhibitory peptides using proteases including pepsin, trypsin, αchymotrypsin, papain, alcalase, and neutrase. The pepsin hydrolysate exhibited the highest ACE inhibitory activity, compared to the other hydrolysates and then was separated into three fractions (F1, F2, and F3) using Sephadex G-25 gel filtration column chromatography. First fraction (F1) showed the highest ACE inhibitory activity and it was further purified into two fractions (F1-1 and F1-2) using reverse-phase high-performance liquid chromatography. The IC 50 value of purified ACE inhibitory peptides were 123 and 173 μM and identified as novel peptides, Gly-Met-Asn-Asn-Leu-Thr-Pro (GMNNLTP; MW, 728 Da) and Leu-Glu-Gln (LEQ; MW, 369 Da), respectively. In addition, nitric oxide production level (%) was significantly increased by the purified peptide (Gly-Met-Asn-Asn-Leu-Thr-Pro) compared to the purified peptide (Leu-Glu-Gln) and other treated pepsin hydrolysate fractions on human umbilical vein endothelial cells (HUVECs). Cell viability assay showed no cytotoxicity on HUVECs with the treated purified peptides and fractions. These results suggest that the isolated peptides from cultured marine microalga, N. oculata protein sources may have potentiality to use commercially as ACE inhibitory agents in functional food industry.
Aquaculture Reports, 2019
We have shown that bitter peptides derived from the hydrolysates of pepsin digested fish protein can increase lymphocytes and lysozyme activity and improve fish survival in aquaculture. In this study, we investigated how the immune function of bitter peptides increases the phagocytes' engulf of latex beads, and analyzed the antioxidation of myofibrillar protein in peeled shrimp during chilled storage with /without bitter peptides by evaluating the activity of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals, and the effects of the total carbonyl and sulfhydryl. Also, the bitter peptides' effect on the structural stability of muscles protein throughout oxidation was examined in vitro by both scanning electron microscope (SEM) and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The engulf assay demonstrated phagocytosis increased from the control group to the highest bitter peptide concentration of 1.2 mg/ml; the bitter peptides had a significant DPPH radicalscavenging activity, reducing the power of ferric ions and metal chelating ability. Chemical analysis showed that myofibrillar protein in chilled storage was highly susceptible to oxidation, and the results indicate that treating peeled shrimp with bitter peptides before chilled storage significantly decreases the formation of carbonyl derivatives and reduces the loss of thiol groups when compared with the water treated sample. In addition, the results of both SEM and SDS-PAGE confirm that there was less distortion of tissue structure and less degradation of the protein in the samples treated with bitter peptides. Bitter peptides are both beneficial for fish disease control and preservation of marine food.
In this study, soft-shelled turtle (Pelodiscus sinensis) egg white (SSTEW) proteins were digested by thermolysin and the resulting small peptides were further fractionated by reverse phase chromatography. Peptides with angiotensin I-converting enzyme inhibitory (ACEI) activity from these fractions were screened. A lysozyme-derived peptide, IW-11, from the fraction with the most effective ACEI was identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and its purified form showed effective ACEI activity in vitro (IC 50 = 4.39 ± 0.31 μM). The Lineweaver-Burk plots indicated that the inhibition towards ACE caused by this peptide is a competitive inhibition. The molecular docking study further revealed that the ACEI activity of IW-11 is mainly attributed to the formation of hydrogen bonds between the N-terminal residue of IW-11 and the S1 pocket (Ala354 and Tyr523) and the S2′ region (His513 and His353) of ACE. Moreover, the digestion parameters were further optimized and the target peptide (82% purity) was readily obtained (15% yield) without any cumbersome purification procedure. Notably, lysozyme C is the most abundant protein in SSTEW, which implies that an efficient production of this ACEI peptide from SSTEW is promising.
Enzyme-Assisted Discovery of Antioxidant Peptides from Edible Marine Invertebrates: A Review
Marine drugs, 2017
Marine invertebrates, such as oysters, mussels, clams, scallop, jellyfishes, squids, prawns, sea cucumbers and sea squirts, are consumed as foods. These edible marine invertebrates are sources of potent bioactive peptides. The last two decades have seen a surge of interest in the discovery of antioxidant peptides from edible marine invertebrates. Enzymatic hydrolysis is an efficient strategy commonly used for releasing antioxidant peptides from food proteins. A growing number of antioxidant peptide sequences have been identified from the enzymatic hydrolysates of edible marine invertebrates. Antioxidant peptides have potential applications in food, pharmaceuticals and cosmetics. In this review, we first give a brief overview of the current state of progress of antioxidant peptide research, with special attention to marine antioxidant peptides. We then focus on 22 investigations which identified 32 antioxidant peptides from enzymatic hydrolysates of edible marine invertebrates. Strat...