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Correction for 'Wheat peptides inhibit the activation of MAPK and NF-κB inflammatory pathways and maintain epithelial barrier integrity in NSAID-induced intestinal epithelial injury' by Zhiyuan Feng et al., Food Funct., 2024, https://doi.org/10.1039/D3FO03954D.
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The use of non-steroidal anti-inflammatory drugs (NSAIDs) has negative effects on the gastrointestinal tract, but the proton pump inhibitors currently in use only protect against gastrointestinal disease and may even make NSAID-induced enteropathy worse. Therefore, new approaches to treating enteropathy are required. This study aimed to investigate the protective effect of wheat peptides (WPs) against NSAID-induced intestinal damage in mice and their mechanism. Here, an in vivo mouse model was built to investigate the protective and reparative effects of different concentrations of WPs on NSAID-induced intestinal injury. WPs ameliorated NSAID-induced weight loss and small intestinal tissue damage in mice. WP treatment inhibited NSAID-induced injury leading to increased levels of oxidative stress and expression levels of inflammatory factors. WPs protected and repaired the integrity and permeability injury of the intestinal tight junction induced by NSAIDs. An in vitro Caco-2 cell model was built with lipopolysaccharide (LPS). WP pretreatment inhibited LPS-induced changes in the Caco-2 cell permeability and elevated the levels of oxidative stress. WPs inhibited LPS-induced phosphorylation of NF-κB p65 and mitogen-activated protein kinase (MAPK) signaling pathways and reduced the expression of inflammatory factors. In addition, WPs increased tight junction protein expression, which contributed to improved intestinal epithelial dysfunction. Our results suggest that WPs can ameliorate NSAID-induced impairment of intestinal barrier functional integrity by improving intestinal oxidative stress levels and reducing inflammatory factor expression through inhibition of NF-κB p65 and MAPK signaling pathway activation. WPs can therefore be used as potential dietary supplements to reduce NSAID-induced injury of the intestine.
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Gastroenteropatias , Enteropatias , Humanos , Camundongos , Animais , NF-kappa B/genética , NF-kappa B/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Triticum/metabolismo , Células CACO-2 , Anti-Inflamatórios não Esteroides/farmacologia , Lipopolissacarídeos/farmacologia , Enteropatias/metabolismo , Peptídeos/farmacologia , Peptídeos/metabolismo , Mucosa Intestinal/metabolismoRESUMO
Fermentation technology was used to prepare the acaí (Euterpe oleracea) fermentation liquid. The optimal fermentation parameters included a strain ratio of Lactobacillus paracasei: Leuconostoc mesenteroides: Lactobacillus plantarum = 0.5:1:1.5, a fermentation time of 6 days, and a nitrogen source supplemental level of 2.5%. In optimal conditions, the ORAC value of the fermentation liquid reached the highest value of 273.28 ± 6.55 µmol/L Trolox, which was 55.85% higher than the raw liquid. In addition, the FRAP value of the acaí, as well as its scavenging ability of DPPH, hydroxyl, and ABTS free radicals, increased after fermentation. Furthermore, after fermentation treatment, the microstructure, basic physicochemical composition, amino acid composition, γ-aminobutyric acid, a variety of volatile components, and so on have changed. Therefore, fermentation treatment can significantly improve the nutritional value and flavor of the acaí. This provides a theoretical basis for the comprehensive utilization of acaí.
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In this study, the effect of corn oligopeptides (COPs) with liver protection activity on mice with hepatic fibrosis (HF) induced by carbon tetrachloride (CCl4 ) was studied. It was proved that COPs can ameliorate the liver injury and inflammation caused by CCl4 by histopathology and enzyme-linked immunosorbent assay in mice. The expression of Akt/NF-κB inflammatory pathway was determined by real-time polymerase chain reaction (RT-PCR) and western blotting (WB). The results showed that COPs inhibited the expression of key proteins in the inflammatory pathway. In conclusion, the results of this study suggested that COPs could improve CCl4 -induced HF by improving liver injury, reducing the expression of inflammatory factors, and inhibiting the expression of inflammatory signaling pathways. PRACTICAL APPLICATIONS: The corns around the world are mainly used as animal feed, and the liver protective activity of corn oligopeptides (COPs) is rarely applied to the market. The development of COPs liver protective food can prevent the occurrence of liver-related diseases such as hepatic fibrosis to a certain extent. Developing COPs liver protecting food can improve the utilization value of corn. It is hoped that this study can provide experimental support for the application of COPs in liver protection food.
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NF-kappa B , Proteínas Proto-Oncogênicas c-akt , Animais , Cirrose Hepática/induzido quimicamente , Cirrose Hepática/tratamento farmacológico , Camundongos , NF-kappa B/genética , NF-kappa B/metabolismo , Oligopeptídeos/farmacologia , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais , Zea mays/metabolismoRESUMO
BACKGROUND: Food allergy is a serious public nutritional health problem that has attracted extensive worldwide attention. Shellfish allergy is a long-lasting disorder that has a lifelong impact on health. Sarcoplasmic calcium-binding protein (SCP) plays a vital role in cell and muscle functions and has been identified as an allergen in oyster. RESULTS: In this study, recombinant SCP (rSCP) with a molecular mass of 21 kDa was produced and identified based on SCP amino acid sequencing of Pacific oyster (Crassostrea gigas), and was used as a follow-up experimental material. Its physicochemical characterization showed that purified rSCP is highly stable to heat and acid-alkali and trypsin digestion but less resistant to pepsin digestion. We established an animal sensitization model and rSCP displayed stronger Immunoglobulin E (IgE)-binding activity with rat serum in the rSCP + cholera toxin (CT) group compared with the CT group and a control group. Five epitope peptides were identified as linear immunodominant epitopes by indirect competitive enzyme-linked immunosorbent assay (icELISA) for the first time. We also found that conformational epitopes may play a major role in the immunoreactivity of SCP. CONCLUSION: These results are significant for understanding hypersensitization of humans to oyster and offer available preventive measures and treatment programs in further research. © 2021 Society of Chemical Industry.
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Alérgenos , Crassostrea , Alérgenos/química , Alérgenos/genética , Sequência de Aminoácidos , Animais , Proteínas de Ligação ao Cálcio/química , Proteínas de Ligação ao Cálcio/genética , Proteínas de Ligação ao Cálcio/metabolismo , Crassostrea/genética , Epitopos/química , RatosRESUMO
BACKGROUND: Corn peptides (CPs) are rich in branched-chain amino acids such as leucine and have a variety of biological activities such as antioxidant and improved lipid distribution. In this article, we prepared CPs by enzymatic digestion of corn proteins and evaluated their anti-fatigue activity. RESULTS: We evaluated the anti-fatigue effect of CPs through an exhaustive swimming experiment. The results showed that CPs were able to significantly reduce the rate of body weight gain and prolong the duration of exhaustive swimming. Besides, CPs reduced blood urea nitrogen (BUN) levels after exercise, while they significantly increased muscle glycogen and liver glycogen stores. They reduced muscle cell damage from exercise. In addition, CPs were effective in increasing AMPK, PGC-1α and PI3K protein expression levels and promoting Akt phosphorylation. Correlation analysis showed that CPs increased the abundance of probiotics such as Lactobacillus and Akkermansia in the gut microflora. CONCLUSION: CPs, which enhanced exercise performance in mice and could modulate gut microbial composition, had significant anti-fatigue activity. © 2021 Society of Chemical Industry.
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Músculo Esquelético , Zea mays , Animais , Bactérias/genética , Bactérias/metabolismo , Fadiga/tratamento farmacológico , Fadiga/metabolismo , Camundongos , Músculo Esquelético/metabolismo , Peptídeos/química , Natação , Zea mays/metabolismoRESUMO
BACKGROUND: Molluscan shellfish, including oysters, often cause allergic reactions in sensitive people throughout the world. It has been demonstrated that arginine kinase (AK) is one of the major allergens of oyster. The present study aimed to evaluate the immunoreactivity and structure of oyster AK as affected by heat treatment, pH change, and in vitro digestion. What is more, the immunoglobulin E-binding epitopes of this allergen were also predicted and validated. RESULTS: Thermal and pH assays revealed that AK was unstable at temperature >40 °C or pH ≤5.0 by sodium dodecyl sulfate polyacrylamide gel electrophoresis and circular dichroism, and the digestibility assays suggested that AK was more easily digested by pepsin than by trypsin and chymotrypsin. The potential epitopes were predicted through immunoinformatics tools, and seven linear epitopes were identified by indirect competition enzyme-linked immunosorbent assay with pooled sera and individual serum from oyster-allergic patients. The critical amino acids in each epitope were also confirmed using mutant peptides. These linear epitopes and critical amino acids were apt to distribute on the outer surface of homology-based AK model. Moreover, the three denaturants (sodium dodecyl sulfate, ß-mercaptoethanol, and urea) can destroy the spatial structure of AK and increase or reduce its allergenicity by denaturation treatments. CONCLUSION: Processing conditions lay the foundation for the variation of allergenicity. Seven linear epitopes and their critical amino acids were identified by indirect competitive enzyme-linked immunosorbent assay. These findings will be helpful in allergy diagnosis and development of hypoallergenic products in the near future. © 2021 Society of Chemical Industry.
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Arginina Quinase , Crassostrea , Alérgenos/química , Sequência de Aminoácidos , Aminoácidos , Animais , Arginina Quinase/química , Arginina Quinase/metabolismo , Epitopos/química , Humanos , Dodecilsulfato de SódioRESUMO
OBJECTIVE: The objective of this work was to develop a peptide production process of the exact molecular weight propitious to topical application for cosmetics and to investigate the effects of enzymolysis-derived peptide on UVB-induced photoaging rat skin. METHODS: The chum salmon fish skins were hydrolyzed by alkaline protease and neutral protease and spray-dried at different conditions, and three kinds of molecular weight peptide (MFSOP) were obtained. A total of 66 ICR rats (female, 20 ± 1 g) were randomly divided into eleven groups, including the normal, model, and experimental groups. The three kinds of MFSOP were dissolved at different dosages (5, 2.5%, and 5%) and then applied on the ICR hairless back skins prior to exposing UVB irradiation of 3000mJ/cm2 to them 4 h later. After 8 weeks, the rats were killed and the hair-shaved skins were tested for skin moisture, hyaluronic acid, hydroxyproline, antioxidant activity, and RNA expression. RESULTS: Three kinds of MFSOP were obtained, with the average molecular weights of 495.16, 1194.00, and 2032.46 Dalton, respectively. The MFSOPs, especially the MFSOP of average molecular weight of 1194.00 Dalton, played an important role in the recovery of the UVB-injured skin tissue in lock in moisture, in antioxidant activity and in promotion in collagen and elastin protein to some extent. CONCLUSION: MFSOPs, especially MFSOP of average molecular weight of 1194.00 Dalton, derived from enzymolysis are potential materials to apply in cosmetics for the UVB9-induced anti-photoaging activity (lock in moisture, antioxidant activity, and promotion in collagen and elastin protein).
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Envelhecimento da Pele , Animais , Antioxidantes/farmacologia , Colágeno , Elastina , Feminino , Humanos , Camundongos , Camundongos Pelados , Peso Molecular , Oligopeptídeos , Peptídeos/farmacologia , Ratos , Pele , Raios Ultravioleta/efeitos adversosRESUMO
Wheat gluten was hydrolyzed with both alkaline protease and neutral protease to produce high-protein and low-wheat-weight oligopeptides (WOP), which was subjected to a multistage purification. Then, high performance liquid chromatography was applied to separate WOP. In order to identify WOP sequences, six major fractions were gathered for mass spectrometry. A total of 15 peptides were synthesized for further in vitro analyses of their antithrombotic activity, vasorelaxation activity, and cholesterol reducing activity. Two antithrombotic peptides (ILPR and ILR), three vasorelaxant peptides (VN, FPQ, and FR), and four cholesterol-lowering peptides (QRQ, ILPR, FPQ, and ILR) were identified. These active peptides in WOP were also quantified. These peptides are novel candidate peptides with vascular disease suppressing effects. The results indicate WOP as good protein sources for multifunctional peptides.
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This study aimed to focus on the high-value utilization of raw wheat gluten by determining the potent antioxidant peptides and angiotensin I-converting enzyme (ACE) inhibitory peptides from wheat gluten oligopeptides (WOP). WOP were analyzed for in vitro antioxidant activity and inhibition of ACE, and the identification of active peptides was performed by reversed-phase high-performance liquid chromatography and mass spectrometry. Quantitative analysis was performed for highly active peptides. Five potent antioxidant peptides, Leu-Tyr, Pro-Tyr, Tyr-Gln, Ala-Pro-Ser-Tyr and Arg-Gly-Gly-Tyr (6.07 ± 0.38, 7.28 ± 0.29, 11.18 ± 1.02, 5.93 ± 0.20 and 9.04 ± 0.47 mmol 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox) equivalent/g sample, respectively), and five potent ACE inhibitory peptides, Leu-Tyr, Leu-Val-Ser, Tyr-Gln, Ala-Pro-Ser-Tyr and Arg-Gly-Gly-Tyr (half maximal inhibitory concentration (IC50) values = 0.31 ± 0.02, 0.60 ± 0.03, 2.00 ± 0.13, 1.47 ± 0.08 and 1.48 ± 0.11 mmol/L, respectively), were observed. The contents of Leu-Tyr, Pro-Tyr, Tyr-Gln, Ala-Pro-Ser-Tyr, Arg-Gly-Gly-Tyr, and Leu-Val-Ser were 155.04 ± 8.36, 2.08 ± 0.12, 1.95 ± 0.06, 22.70 ± 1.35, 0.25 ± 0.01, and 53.01 ± 2.73 µg/g, respectively, in the WOP. Pro-Tyr, Tyr-Gln, Ala-Pro-Ser-Tyr, Arg-Gly-Gly-Tyr, and Leu-Val-Ser are novel antioxidative/ACE inhibitory peptides that have not been previously reported. The results suggest that WOP could potentially be applied in the food industry as a functional additive.
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Inibidores da Enzima Conversora de Angiotensina/farmacologia , Antioxidantes/química , Glutens/química , Peptidil Dipeptidase A/genética , Sequência de Aminoácidos , Inibidores da Enzima Conversora de Angiotensina/química , Angiotensinas/genética , Antioxidantes/farmacologia , Glutens/farmacologia , Espectrometria de Massas , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/farmacologia , Peptídeos/química , Peptídeos/farmacologia , Peptidil Dipeptidase A/efeitos dos fármacos , Triticum/químicaRESUMO
This study aimed to evaluate the effect of oyster peptides and oyster powder on the procreative capacity of rats displaying reproductive dysfunction induced by cyclophosphamide (CTX). The amino acid composition and relative molecular mass of the oyster peptides and oyster powder were detected using an automatic amino acid analyzer and high-performance liquid chromatography (HPLC). After 5 d of exposure to CTX and six weeks of oyster peptide and oyster powder treatment, the biochemical serum indexes of the rats, the expression of related genes and proteins in the testes, as well as the antioxidant status and pathological state of the testes and kidneys were examined. The results showed that oyster peptides could effectively improve the biochemical blood indexes of rats, and increase the level of androgen in the blood, while improving the pathological state and oxidative stress state of the kidneys and testes, therefore, exhibiting a beneficial effect on reproductive injury. PRACTICAL APPLICATIONS: This study examined the activity of oyster peptides and their ability to enhance the procreative capacity of rats with reproductive dysfunction induced by CTX while analyzing the amino acid composition and relative molecular mass of the oyster peptides. The results of this experiment provided a preliminary theoretical basis for the development of new functional foods using oyster peptides.
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Ostreidae , Peptídeos , Animais , Ciclofosfamida/toxicidade , Masculino , Pós , Proteínas , RatosRESUMO
This study assessed the melanogenesis effects of rice protein hydrolysate (RPH) and explored the underlying molecular mechanism of its characteristic peptides. In this investigation, human epidermal melanocyte (PIG1) cells were used to establish a UVB-induced model to evaluate the effect of RPH on melanin content, tyrosinase activity, and reactive oxygen species (ROS) levels. High performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was employed to identify the peptide composition (2-4 amino acids) in RPH. Enzymatic hydrolysis was employed to screen the characteristic peptides Leu-Leu-Lys (LLK), Leu-Pro-Lys (LPK), and pyroGlu-Lys (pEK), while their effect on the molecular mechanism involved in the melanin synthesis process was further explored using quantitative real-time polymerase chain reaction (PCR) and western blotting. The results indicated that RPH reduced the melanin content, tyrosinase activity, and ROS production in PIG1 cells. The selected peptides LLK, LPK, and pEK from RPH reduced the expression of tyrosinase-related protein 1 (TRP-1) and tyrosinase-related protein 2 (TRP-2) and affected melanin synthesis by regulating the JNK/ß-Trcp/NFκB-p65/MITF signaling pathway at the mRNA and protein levels. This study shows that RPH plays a vital role in the melanogenesis process, therefore, providing a theoretical basis for the use of RPH as a novel additive product.
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Melaninas/biossíntese , Oryza/química , Peptídeos/farmacologia , Proteínas de Vegetais Comestíveis/farmacologia , Hidrolisados de Proteína/farmacologia , Humanos , Hidrólise , Espectrometria de Massas , Melanócitos/efeitos dos fármacos , Melanoma Experimental , Monofenol Mono-Oxigenase/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Transdução de Sinais/efeitos dos fármacosRESUMO
This study evaluated the effect of four peptides, VLP, LLP, LL, and LL from pea on regulating glucose metabolism and antioxidant through IRS-1/PI3K/AKT and p38MAPK signal pathway in IR-HepG2 cell induced by 10-6 M insulin. The genes expression of PEPCK, G6Pase, GLUT2, and IRS-1 and proteins of IRS-1, p(Ser307)-IRS-1, AKT, p(Ser473)-AKT, p38MAPK, and p-p38MAPK were determined by RT-PCR and western blotting, respectively. Results show that they displayed highly potent on stimulation glucose metabolism and relief oxidative stress in IR-HepG2 cells. VLP, LLP, VA, and LL reduced Ser307 phosphorylation of IRS-1 and promoted Ser473 phosphorylation of AKT. Among them, LLP, VA, and LL increased the expression both gene and protein of GLUT2, and VLP and LL reduced p38MAPK phosphorylation showing strong antioxidant capacity. Therefore, pea oligopeptides have considerable potential for reversing the metabolic abnormalities associated with type 2 diabetes. PRACTICAL APPLICATIONS: This paper examined the intervention effect of VLP, LLP, VA, and LL that from pea on insulin resistance, and the mechanisms were detected by western blotting. The results provide a theoretical knowledge for the prevention of insulin resistance in T2D of pea-derived peptides and lay the foundation for the development of functional products and drugs in the future.
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Diabetes Mellitus Tipo 2 , Resistência à Insulina , Pisum sativum , Células Hep G2 , Humanos , Peptídeos , Fosfatidilinositol 3-Quinases , Extratos Vegetais , Proteínas Proto-Oncogênicas c-akt/genética , Espécies Reativas de OxigênioRESUMO
Design of hypoallergen with low IgE reactivity is desirable for allergen-specific immunotherapy. Despite oyster tropomyosin (Cra g 1) is considered as the major allergen, no immunotherapy is available now. In the current research, we generated hypoallergens of Cra g 1 and evaluated their allergenicity. Four hypoallergenic derivatives were constructed by epitope deletion or site-directed mutagenesis on grounds of the identified epitopes. They showed obvious reduction in reactivity towards IgE from oyster-allergic patients and Cra g 1-sensitized BN rats, as well as significant decrease in degranulation and secretion of allergic mediators including histamine, IL-4, IL-6 and TNF-α. In addition, to further investigate the molecular mechanism, we examined the effects of these variants on FcεRI-dependent signalling pathway in IgE-challenged RBL-2H3 cells. We found that the hypoallergenic mutants were able to attenuate FcεRI-mediated signaling cascades in tested cells. These results indicate that the hypoallergenic molecules have ideal characteristics and offer a promising new strategy in clinical immunotherapy for shellfish-allergic subjects.
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Alérgenos/imunologia , Hipersensibilidade/imunologia , Ostreidae/imunologia , Tropomiosina/imunologia , Sequência de Aminoácidos , Animais , Linhagem Celular , Dessensibilização Imunológica/métodos , Epitopos/imunologia , Feminino , Imunoglobulina E/imunologia , Ratos , Ratos Endogâmicos BN , Frutos do Mar , Transdução de Sinais/imunologiaRESUMO
INTRODUCTION AND OBJECTIVES: The production and consumption of oysters is increasing annually because it can provide essential nutrients and benefit for human health, leading to frequent occurrence of severe allergic reactions observed in sensitized individuals. The aim of the present study was to investigate the effects of acid and protease treatment on the conformation and IgE-binding capacity of recombinant Crassostrea gigas tropomyosin (Cra g 1). RESULTS: Under acidic conditions, Cra g 1 did not undergo degradation, however, the changes obvious in the intensity of CD signal and ANS-binding fluorescence were observed, which was associated with a decrease in antibody reactivity. In simulated gastrointestinal fluid (SGF) and simulated intestinal fluid (SIF) digestion system, acid-treated Cra g 1 was relatively resistant to digestion, but the degradative patterns were very different. Moreover, owing to alterations of secondary structure and hydrophobic surface of the protein during digestive processing, antigenicity of acid-induced Cra g 1 reduced in SGF while it increased significantly in SIF. CONCLUSION: To our knowledge, this is the first study reporting that antigenicity of acid-treated oyster tropomyosin increased after SIF digestion. These results revealed that treatment with acid and pepsin, rather than trypsin, was an effective way of reducing IgE-binding capacity of tropomyosin from oyster.
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Ácidos/metabolismo , Alérgenos/imunologia , Imunoglobulina E/imunologia , Tropomiosina/imunologia , Ácidos/análise , Alérgenos/química , Alérgenos/metabolismo , Afinidade de Anticorpos , Suco Gástrico/química , Suco Gástrico/metabolismo , Humanos , Secreções Intestinais/química , Secreções Intestinais/metabolismo , Pepsina A/análise , Pepsina A/metabolismo , Conformação Proteica , Proteínas Recombinantes/química , Proteínas Recombinantes/imunologia , Proteínas Recombinantes/metabolismo , Tropomiosina/química , Tropomiosina/metabolismo , Tripsina/análise , Tripsina/metabolismoRESUMO
The aim of this study was to evaluate the hypoglycemic effects of Pea oligopeptide on the glycemic and lipidemic status of mice with type 2 diabetes (T2D) induced by a high-fat diet and streptozotocin (STZ). Using HPLC-MS/MS spectra processing, 70 significant peptide (2-3 amino acids) sequences were identified, noting four peptides from Pea oligopeptide with a proline residue at the C-terminus, which might have dipeptidase-IV (DPP-IV) inhibitory activity for the treatment of T2D. After a 4-week administration of Pea oligopeptide and metformin, various blood biochemical indexes and organic histopathologies were detected to aid the discussion regarding potential mechanisms. The results showed a significant reduction in the levels of blood glucose, lipid profiles, and liver fat deposition in diabetic mice. Furthermore, Pea oligopeptide and metformin improved glucose tolerance, promoted glycogen synthesis, and protected the liver and kidney structures in diabetic mice. The results indicated that Pea oligopeptide played an essential role in the hypoglycemic effect in the T2D mice model. Practical applications This paper examined the preliminary hypoglycemic activities of Pea oligopeptide in a high-fat diet and STZ-induced T2D mice. Furthermore, four kinds of dipeptides and tripeptides that might exhibit antidiabetic functions were detected using HPLC-MS/MS. The results provided practical knowledge regarding the hypoglycemic effects of Pea oligopeptide and established the foundation of its structure-function relationships.
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Glicemia/análise , Glicogênio/sangue , Insulina/sangue , Lipídeos/sangue , Metformina/farmacologia , Oligopeptídeos/farmacologia , Estreptozocina/efeitos adversos , Animais , Diabetes Mellitus Experimental , Diabetes Mellitus Tipo 2 , Dieta Hiperlipídica , Hipoglicemiantes , Camundongos , Pisum sativumRESUMO
Corn gluten hydrolysate (CGH) was prepared by food-grade bacterial proteases, alcalase and neutral protease. Digestion of CGH with carboxypeptidase A and leucine aminopeptidase extensively changed the elution patterns of peptides as observed from reversed phase high performance liquid chromatography-mass spectrometry (LC-MS), whereas digestion with pepsin and trypsin hardly affected the elution patterns. Twenty-five major peptides in CGH were identified. After digestion with exopeptidases, only prolyl dipeptides and pyroglutamyl di- and tripeptides remained, whereas the other 17 peptides completely disappeared. On the other hand, all 25 peptides remained after digestion with pepsin and trypsin. These facts suggest that a majority of short-chain peptides in food protein hydrolysates are degraded by exopeptidases during digestion and absorption processes. Thus, susceptibility to exopeptidases should be considered for prediction of bioactive peptide upon ingestion, which has not been considered in most of previous studies on food-derived bioactive peptides.
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Proteínas de Bactérias/química , Glutens/química , Peptídeo Hidrolases/química , Peptídeos/química , Zea mays/química , Bacillus/enzimologia , Biocatálise , Exopeptidases/química , Espectrometria de Massas , Hidrolisados de Proteína/químicaRESUMO
Shellfish, including oysters, often cause allergic reactions in children and adults. Oysters are inevitably consumed because of its delicacy and nutritional benefit, leading to frequent occurrence of severe clinical symptoms observed in patients with oyster hypersensitivity. We aimed to identify the immunodominant epitopes of oyster tropomyosin and crucial amino acids for IgE binding, which will help us to further understand the immunochemical characteristics of Cra g 1. The potential epitopes were predicted by immunoinformatics tools and the resultant immunodominant epitopes were identified by inhibition ELISA with pooled sera and individual serum from oyster allergic patients. Surprisingly, homologous substitution of multiple amino acids led to obviously decrease affinity of IgE antibodies, but this manner did not abrogate binding completely. Five major linear epitopes were evenly distributed on the surface of homology-based Cra g 1 model and hydrophilic residues appeared to be the most important for IgE binding. These results not only offer a better understanding of the molecular mechanism of interaction between Cra g 1 and oyster-specific IgE but also have significance in clinical diagnosis and immunotherapy.
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Alérgenos/genética , Epitopos Imunodominantes/genética , Ostreidae/genética , Tropomiosina/genética , Adulto , Alérgenos/imunologia , Sequência de Aminoácidos , Animais , Humanos , Epitopos Imunodominantes/imunologia , Imunoglobulina E/sangue , Imunoglobulina E/imunologia , Mutação , Ostreidae/imunologia , Hipersensibilidade a Frutos do Mar , Tropomiosina/imunologiaRESUMO
Corn protein has been identified as an important source of bioactive peptides. Such peptides can be released during hydrolysis induced by proteolytic enzymes or microbial fermentation. Corn peptides have been found to exhibit different functions in vitro and in vivo such as antihypertensive, hepatoprotective, anti-obesity, antimicrobial, antioxidative, mineral-binding and accelerating alcohol metabolism. To date, 22 sequences of bioactive corn peptides have already been identified. There is an increasing commercial interest in the production of corn peptides with the purpose of using them as active ingredients, which may find use in the treatment of liver injury, hypertension, dental carries, oxidative stress, mineral malabsorption and obesity. These bioactive peptides may be used in formulation of functional foods, nutraceuticals, and natural drugs because of their health benefit effects.
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Glutens/química , Peptídeos/química , Peptídeos/farmacologia , Zea mays/química , Animais , Fermentação , Humanos , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Proteínas de Plantas/farmacologiaRESUMO
BACKGROUND: Shellfish, including oysters, often cause allergic reactions in adults. Thermal treatment is one of the most common technologies for dealing with seafood, which may affect biological properties. The present study aimed to evaluate the impact of heating on the conformation and potential allergenicity of oyster-derived tropomyosin (Cra g 1). RESULTS: Sodium dodecylsulphate-polyacrylamide gel electrophoresis showed that there was an apparent band at 35 kDa of raw tropomyosin after purification and more significant polymers appeared in the heated protein. Interestingly, obvious changes in the intensity of the circular dichroism signal and 1-anilino-8-naphthalene sulfonate-binding fluorescence were observed especially in the case of the roasted form, which was associated with an increase in antibody reactivity. The degree of immunoglobulin (Ig)E binding of this treatment was demonstrated in the order roasted > boiled > raw. Furthermore, sequence alignment and amino acid composition revealed that Cra g 1 shared relatively high homology to tropomyosins from other shellfish and was also abundant in lysine that was apt to be modified by reducing sugars during heating. CONCLUSION: Heated Cra g 1 produces higher IgE reactivity than the raw form as a result of the denaturation and formation of polymers. These findings will benefit the diagnosis and management of potential allergenicity as a result of shellfish. © 2018 Society of Chemical Industry.