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1.
Phys Chem Chem Phys ; 24(19): 11791-11800, 2022 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-35506877

RESUMO

The hyperphosphorylated protein phosvitin (PV) undergoes a pH-dependent transition between PII- and ß-sheet secondary structures, a process deemed crucial for its role in the promotion of biogenic apatite formation. The transition occurs surprisingly slowly (minutes to hours). This is consistent with a slow aggregation process involving ionic interactions of charged groups on the protein surface. Herein, we determined the associated transition pK values and time constants through matrix least-squares (MLS) global fitting of a series of pH- and time-dependent circular dichroism (CD) spectra recorded in the presence of different mono-, bi- and trivalent cations. Supporting our results with dynamic light scattering data, we clearly identified a close correlation of ß-sheet transition and the formation of small aggregates at low pH. This process is inhibited in the presence of all tested cations with the strongest effects for trivalent cations (Fe3+ and Al3+). In the presence of Ca2+ and Mg2+, larger higher-order particles are formed from PV in the ß-sheet conformation, as identified from the interpretation of differential scattering observed in the CD spectra. Our observations are consistent with the existence of a multi-step equilibrium between aggregated and non-aggregated species of PV. The equilibrium is highly sensitive to the environment pH and salt concentration with exceptional behavior in the presence of divalent cations such as Ca2+ and Mg2+.


Assuntos
Fosfoproteínas , Fosvitina , Cátions Bivalentes/química , Dicroísmo Circular , Concentração de Íons de Hidrogênio , Conformação Proteica em Folha beta , Estrutura Secundária de Proteína
2.
Eur J Pharmacol ; 920: 174833, 2022 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-35183532

RESUMO

The closure of skin wounds is indispensable for resistance against pathogens, and fibroblast plays a critical role in skin wound healing. Our previous study demonstrates that the phosvitin-derived small peptide Pt5-1c not only possesses broad-spectrum antimicrobial activity but also exhibits synergistic effect and antibiofilm activity with traditional antibiotics against bacteria, including multi-drug resistant (MDR) strains. Here we provided the first evidence that Pt5-1c promoted the wound closure of surrogate scratch "wounds" of fibroblasts in vitro, and speeded up the healing and re-epithelialization of murine dermal wounds in vivo. We also showed that Pt5-1c activated migration of fibroblasts via a combined action of inducing migratory phenotype and trans-activating epidermal growth factor receptor (EGFR). Moreover, Pt5-1c accelerated attachment and proliferation of fibroblasts in vitro. Interestingly, Pt5-1c was able to promote collagen contraction through activation/differentiation of fibroblasts into myofibroblasts. These data together suggest that Pt5-1c is a promising candidate with therapeutic potential to promote wound healing.


Assuntos
Fosvitina , Cicatrização , Animais , Movimento Celular , Proliferação de Células , Fibroblastos , Camundongos , Miofibroblastos , Peptídeos/farmacologia , Fosvitina/metabolismo , Fosvitina/farmacologia , Pele
3.
Food Chem ; 371: 131077, 2022 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-34536655

RESUMO

Egg yolk granules are supramolecular assembly of high-density lipoproteins and phosvitin driven by calcium bridges. However, applications of granules are severely restricted by the large particle size and poor water dispersibility. This study revealed the Janus effects of NaCl on structure of granules at varied pH values. Addition of 0.3-0.5 M NaCl led to the dissociation of at pH 5.0-7.0. At pH 5.0-10.0, dissociated granules demonstrated good colloidal stability with NaCl because of the adsorption of highly hydrated Na+ and Ca2+, which provided strong hydration repulsion when electrostatic repulsion was screened. In contrast, at pH 2.0 and 3.0, dissociated granules were positively charged with adsorption of poorly hydrated Cl- as counterions. Cl- failed to give sufficient hydration repulsion, leading to the phase separation with 0.3-0.5 M NaCl. Similar effects have been also found in LiCl, KCl, and CsCl, but Li+ might be less effective to disrupt calcium bridges.


Assuntos
Gema de Ovo , Cloreto de Sódio , Tamanho da Partícula , Fosvitina , Água
4.
Food Res Int ; 141: 110169, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33642025

RESUMO

A new peptide with strong calcium binding capacity was isolated from phosvitin hydrolysates. Taking calcium chelating rate as an indicator, phosvitin hydrolysates were separated gradually by anion-exchange chromatography, gel filtration chromatography and reversed-phase high performance liquid chromatography. A peptide with a molecular weight of 1106.44402 Da was identified by liquid chromatography-electrospray/mass spectrometry (LC-ESI/MS), and its amino acid sequence was DEEENDQVK, the calcium binding capacity reached 151.10 ± 3.57 mg/g. Its chelating mechanism was investigated. Results showed that, the ß-sheet structure of peptide increased after adding calcium ion, and the main binding sites were carboxyl oxygen atom and amino nitrogen atom. In vitro simulated digestion experiments showed that, the solubility and dialysis rate of calcium in peptide-calcium chelate were higher than those in CaCO3 and D-calcium gluconate. This finding would promote the development of calcium supplements from food resources.


Assuntos
Cálcio , Hidrolisados de Proteína , Peptídeos , Fosvitina , Diálise Renal
5.
Poult Sci ; 100(2): 527-536, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33518105

RESUMO

Phosvitin (PV) from egg yolk is an excellent substrate for the production of phosphopeptides, which have a strong calcium chelating capacity and promoting calcium absorption and bone mineralization. This study investigated the effect of PV hydrolysates produced using a effective preparation method (high temperature (121°C) and mild pressure (0.1 MPa), HTMP) or HTMP pretreatment and trypsin hydrolysis combination (HTMP-PV18) on the physiology of an osteoblast MC3T3-E1 cells line. The proliferation, apoptosis, and differentiation of MC3T3-E1 cells were analyzed using the CCK-8, flow cytometry, and RT-PCR reactions, respectively. Both the HTMP-PV and HTMP-PV18 increased the proliferation, and inhibited the apoptosis of MC3T3-E1 cells significantly. The HTMP-PV increased the proliferation of MC3T3-E1 cells by 147.12 ± 2.11% and the HTMP-PV18 by 136.43 ± 4.51%. In addition, the HTMP-PV and HTMP-PV18 effectively promoted the expression of genes related to the OPG/RANKL signaling channel during cell differentiation. This indicated that both the HTMP-PV and HTMP-PV18 have the potential to promote bone mineralization by improving the proliferation and differentiation of osteoblastic cells.


Assuntos
Fosfopeptídeos/metabolismo , Fosvitina/metabolismo , Células 3T3 , Animais , Diferenciação Celular , Proliferação de Células , Galinhas , Citometria de Fluxo , Hidrólise , Camundongos , Osteoblastos/citologia , Reação em Cadeia da Polimerase em Tempo Real , Transdução de Sinais , Tripsina
6.
Food Chem ; 346: 128903, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33429299

RESUMO

Phosvitin (PSV) is considered as a good emulsifier, although it has a low proportion of hydrophobic regions and steric hindrance. Wheat gluten (WG) possesses excellent hydrophobicity and macromolecular network structure. In this work, WG was subjected to a series of Na2SO3 solution, followed by cross-linking with PSV under transglutaminase (TGase) catalyzation. The results showed that Na2SO3 could break disulfide bonds of WG and increase its solubility from 7.33% to 42.82% with 1200 mg/L of Na2SO3. Correspondingly, the cross-linking degree was significantly enhanced. Compared to PSV, the cross-linked PSV-WG exhibited a higher surface hydrophobicity and thermal stability, with a lower zeta potential and apparent viscosity. The emulsifying activity of PSV-WG reached 17.42, 20.63 and 20.28 m2/g with Na2SO3 concentration of 300, 600 and 900 mg/L, which were all higher than that of PSV (15.19 m2/g). This work provided a novel strategy to elevate emulsifying properties of PSV by cross-link reaction.


Assuntos
Glutens/metabolismo , Fosvitina/metabolismo , Sulfatos/química , Transglutaminases/metabolismo , Biocatálise , Dissulfetos/química , Emulsificantes/química , Glutens/química , Interações Hidrofóbicas e Hidrofílicas , Peso Molecular , Fosvitina/química , Solubilidade , Temperatura , Triticum/metabolismo , Viscosidade
7.
Nutrients ; 12(10)2020 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-33007855

RESUMO

Phosphorylated proteins from food sources have been investigated as regulators of bone formation with potential benefits in treating osteoporosis. Egg, a cheap and nutritious food, is also the source of various proteins and bioactive peptides with applications in human health. Egg yolk is rich in phosvitin, the most phosphorylated protein in nature. Phosvitin has been shown to improve bone health in experimental animals, although the molecular mechanisms and its specific effects on bone-forming osteoblastic cells are incompletely understood. Previous work in our group has identified pancreatin-generated phosvitin phospho-peptides (PPP) as a potential source for bioactive peptides. Given this background, we examined the roles of both phosvitin and PPP in the function of osteoblastic cells. Our results demonstrated their potential to improve bone health by promoting osteoblast differentiation and proliferation, suppressing osteoclast recruitment and the deposition of extracellular matrix, although PPP appeared to demonstrate superior osteogenic functions compared to phosvitin alone.


Assuntos
Proteínas do Ovo/química , Osteoblastos/efeitos dos fármacos , Osteogênese/efeitos dos fármacos , Fosfopeptídeos/química , Fosvitina/farmacologia , Células 3T3 , Animais , Diferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Matriz Extracelular/efeitos dos fármacos , Camundongos , Pancreatina/metabolismo , Fosforilação , Fosvitina/química
8.
J Food Sci ; 85(10): 2969-2976, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32966601

RESUMO

Phosvitin, one of the most noteworthy bioactive components of hen egg yolk, is an amphiphilic protein that stands out with its unique composition and functionality in the food industry and health. Phosvitin consists of 4% of egg yolk dry matter and 11% of egg yolk proteins. It is considered as the most phosphorylated protein with 10% phosphorus. Besides, some potential novel phosphopeptides containing clusters of phosphoserines can be derived from hen's egg yolk phosvitin. Phosvitin, which has many functional features thanks to its unique structure, is known primarily for its metal bonds binding (iron, calcium, etc.) feature. On the other hand, its phosphopeptides may increase the bioavailability of metals compared to phosvitin. Although this feature of phosvitin may partially decrease the bioavailability of especially iron in the egg, it allows the phosvitin to have many bioactivities in the food industry and health. Lipid oxidation, which is a serious problem in the food industry, can be inhibited by adding phosvitin and its derived phosphopeptides to the food production chain via inhibiting bivalent iron. Because phosvitin is an amphiphilic protein capable of chelating, it also shows potential antibacterial effects against the Gram-negative bacteria. Moreover, the literature has recently been attempting to define the promising relationship between phosvitin and its phosphopeptides and plenty of health-promoting activities such as immune-enhancing, melanogenesis inhibitor, anti-ageing, and anticancer. In this review, current information on the hen's egg yolk phosvitin and its phosphopeptides and their bioactivities in the food industry and health are discussed and some future directions are given.


Assuntos
Gema de Ovo/química , Fosvitina/farmacologia , Animais , Galinhas , Feminino , Indústria Alimentícia , Humanos , Valor Nutritivo , Fosvitina/análise , Fosvitina/química
9.
Food Chem ; 321: 126696, 2020 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-32247184

RESUMO

Egg yolk phosvitin is of particular interest due to its functional and biological properties. Recently, it was demonstrated that high hydrostatic pressure (HHP) (400 MPa for 5 min) induced the transfer of folic acid and phosvitin from the egg yolk granule to the plasma fraction. A granule fraction (Gin) produced by egg yolk centrifugation was pressure-treated at 400 and 600 MPa for 5 and 10 min, and centrifuged to generate granule fractions (GP1 to GP4) and plasmas (PP1 to PP4). Iron and phosphorus contents were also increased in PP1 to PP4 fractions, confirming the transfer of phosvitins from pressure-treated granule to plasma. Pressurization drastically improved phosvitin recovery in PP fractions, specifically at 600 MPa for 10 min, which had the highest value of phosvitin/100 mg of dry plasma at 33.3 ± 4.39 mg. Consequently, HHP represents an alternative approach for phosvitin transfer and recovery in the egg yolk soluble fraction.


Assuntos
Gema de Ovo/química , Fosvitina/química , Animais , Centrifugação , Fracionamento Químico , Galinhas , Ácido Fólico/química , Pressão Hidrostática , Fosvitina/isolamento & purificação
10.
J Agric Food Chem ; 68(19): 5437-5447, 2020 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-32320610

RESUMO

The purpose of this work was to conjugate phosvitin (Pv) with gallic acid (GA) to explore a new emulsifier that had both good emulsifying properties and antioxidant activity. The Pv-GA complex was prepared at a GA concentration of 1.5 mg/mL with pH 9.0. The Pv-GA complex obtained was identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and characterized with infrared, ultraviolet, and fluorescence spectra. The emulsifying activity and stability of the Pv-GA complex were slightly improved, and antioxidant activities was significantly enhanced. Furthermore, the Pv-GA complex was used to load conjugated linoleic acid (CLA) for microemulsion preparation. Results showed that the Pv-GA complex could increase the viscosity and lipid antioxidant capacity of Pv-GA/CLA microemulsion. The Pv-GA/CLA microemulsion had remarkable emulsifying activity, emulsifying stability, pH, and thermal stability and poor salt stability.


Assuntos
Emulsificantes/química , Ácido Gálico/química , Fosvitina/química , Antioxidantes/química , Emulsões/química , Concentração de Íons de Hidrogênio , Ácido Linoleico/química , Espectrometria de Massas
11.
Allergol Int ; 69(2): 253-260, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31708435

RESUMO

BACKGROUND: Fish roe allergy is a common health problem in countries where sea food is a major part of the diet, such as Japan. ß'-component (ß'-c) in fish roe has been identified as a major antigen for patients who show hypersensitivity to various fish roes. However, little is known about causative antigens for patients reactive to fish roe of specific species. METHODS: Serum and basophils were obtained from patients who had reactivity to roes of Gadus chalcogrammus (GC) and/or other fish species. GC roe specific antigens were analyzed by immunoblotting, histamine release assay (HRA) and mass spectrometry. Recombinant-fragments of vitellogenin (Vg) were obtained by the Escherichia coli expression system. RESULTS: Serum IgE of a patient with specific reactions to GC roe bound to 15, 28, 40 and 70 kDa-proteins in GC roe extract. Mass spectrometry analysis revealed that proteins in these bands contained fragments corresponding to Vg. Immunoblotting of Vg immunoprecipitated by rabbit anti-Vg antiserum from the extract revealed 15, 28 and 54 kDa fragments bound by the patient's IgE. These bindings were inhibited by the pretreatment of recombinant phosvitin (rPv) and ß'-c (rß'-c). Fractions obtained by native gel electrophoresis containing 15, 28 and 54 kDa proteins, but not the other fractions, induced significant histamine release from the patient's basophils. Sera of the other patients with GC roe specific-IgE showed IgE binding to rPv and/or rß'-c. CONCLUSIONS: The 15, 28 and 54 kDa-fragments of Vg which include structures of Pv and ß'-c, could be antigens for GC roe specific type-I-hypersensitivity.


Assuntos
Proteínas do Ovo/imunologia , Hipersensibilidade Alimentar/imunologia , Hipersensibilidade Imediata/imunologia , Fosvitina/imunologia , Vitelogeninas/imunologia , Adolescente , Animais , Criança , Feminino , Peixes , Hipersensibilidade Alimentar/diagnóstico , Humanos , Hipersensibilidade Imediata/diagnóstico , Immunoblotting , Imunoglobulina E/metabolismo , Japão , Masculino
12.
Br Poult Sci ; 61(1): 17-21, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31661977

RESUMO

1. Phosvitin, a major phosphoprotein found in egg yolk, has strong antioxidant activity. Activation of elastase, collagenase, and hyaluronidase by reactive oxygen species are related to the degradation of ECM and skin aging. The objective of this study was to determine the anti-elastase and anti-hyaluronidase activity of phosvitin.2. Elastase from porcine pancreas and hyaluronidase from bovine testes were used to study the inhibitory activity of phosvitin. To elucidate the mechanism of enzyme inhibition, a Lineweaver-Burk plot was constructed.3. Phosvitin inhibited elastase and hyaluronidase activity in a dose-dependent manner. The IC50 value of phosvitin was 31.6 µg/ml and 1,270 µg/ml against elastase and hyaluronidase, respectively. The analysis of elastase and hyaluronidase kinetics indicated that the apparent Michaelis constant (appKm) was increased by phosvitin but the Vmax value was not affected.4. In conclusion, phosvitin exhibited competitive inhibitory activity against elastase and hyaluronidase. Thus, phosvitin could be used as a natural anti-aging agent in the cosmetics industry.


Assuntos
Gema de Ovo , Fosvitina , Animais , Bovinos , Galinhas , Feminino , Hialuronoglucosaminidase , Suínos
13.
J Agric Food Chem ; 67(51): 14086-14101, 2019 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-31766846

RESUMO

The effect of high-temperature and mild-pressure (HTMP) pretreatment on the enzymatic hydrolysis of phosvitin and the structural characteristics of the phosphopeptides produced were analyzed using tandem mass spectrometry. The HTMP pretreatment hydrolyzed phosvitin at random sites and helped the subsequent enzyme hydrolysis of the peptides produced. With the HTMP pretreatment alone, 154 peptides were produced, while the use of trypsin, Protex 6L, and Multifect 14L in combination with the pretreatment produced 252, 280, and 164 peptides, respectively. The use of two enzyme combinations (trypsin + Protex 6L and trypsin + Multifect 14L) helped the hydrolysis further. The number of phosphopeptides produced increased when the modifications within the same amino acid sequences were considered. This study indicated that HTMP pretreatment was a breakthrough method to improve the enzymatic hydrolysis of phosvitin that enabled an easy production of phosvitin phosphopeptides for their subsequent functional characterizations.


Assuntos
Métodos Analíticos de Preparação de Amostras/métodos , Fosfopeptídeos/química , Fosvitina/química , Sequência de Aminoácidos , Animais , Biocatálise , Galinhas , Hidrólise , Peptídeos/química , Espectrometria de Massas em Tandem , Tripsina/química
14.
Chemistry ; 25(53): 12332-12341, 2019 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-31206850

RESUMO

The development of the nuclear industry has raised multiple questions about its impact on the biotope and humans. Proteins are key biomolecules in cell machinery and essential in deciphering toxicological processes. Phosvitin was chosen as a relevant model for phosphorylated proteins because of its important role as an iron, calcium, and magnesium storage protein in egg yolk. A multitechnique spectroscopic investigation was performed to reveal the coordination geometry of two oxocations of the actinide family (actinyl UVI , NpV ) in speciation with phosvitin. IR spectroscopy revealed phosphoryl groups as the main functional groups interacting with UVI . This was confirmed through laser luminescence spectroscopy (U) and UV/Vis absorption spectroscopy (Np). For UVI , X-ray absorption spectroscopy at the LIII edge revealed a small contribution of bidentate binding present, along with predominantly monodentate binding of phosphoryl groups; for NpV , uniquely bidentate binding was revealed. As a perspective to this work, X-ray absorption spectroscopy speciation of UVI and NpV in the extracted yolk of living eggs of the dogfish Scyliorhinus canicula was determined; this corroborated the binding of phosphorous together with a reduction of the actinyl moiety. Such data are essential to pinpoint the mechanisms of heavy metals (actinyls) accumulation and toxicity in oviparous organisms, and therefore, contribute to a shift from descriptive approaches to predictive toxicology.


Assuntos
Gema de Ovo/metabolismo , Fosvitina/metabolismo , Cálcio/metabolismo , Humanos , Ferro/metabolismo , Magnésio/metabolismo , Minerais , Fósforo/química , Fosvitina/química , Espectroscopia por Absorção de Raios X
15.
Food Funct ; 10(5): 2805-2816, 2019 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-31049530

RESUMO

Egg phosvitin has been traditionally considered as a nutritionally negative protein for its low digestibility in the gastrointestinal tract. Whether it could exert nutritional functions in the large intestine is not known. In this work, the influence of phosvitin on luminal microbiota composition and mucosal transcriptome was investigated with young (3-week) and adult (8-week) mouse models. In young groups, phosvitin mainly suppressed genes related to lipid metabolism, whereas the regulated genes in adult individuals encompassed various biological processes, such as carbohydrate metabolism, sigestive system and others. Phosvitin increased the proportion of Bifidobacterium in the young group, and reduced amounts of pathogenic microbes in the adult group, including Helicobacter and Mucispirillum. There was a close relationship between gene expression changes and abundance of bacteria. Finally, phosvitin reduced the ammonia concentrations in feces for both young and adult groups. These findings suggested that phosvitin modified the large intestinal ecosystem, exhibiting potentially beneficial effects on gut health.


Assuntos
Bactérias/genética , Colo/microbiologia , Gema de Ovo/metabolismo , Microbioma Gastrointestinal , Mucosa Intestinal/microbiologia , Fosvitina/metabolismo , Animais , Bactérias/classificação , Bactérias/isolamento & purificação , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Galinhas , Gema de Ovo/química , Mucosa Intestinal/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Transcrição Genética
16.
Food Funct ; 10(4): 1808-1815, 2019 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-30882809

RESUMO

Phosvitin phosphopeptides (PPP) effectively enhanced calcium bioavailability via inhibiting calcium-phosphate deposition. It is difficult to hydrolyze native phosvitin (PSV) to release PPP due to its compact structure. Polysaccharide conjugation could improve the biofunctional properties of proteins via altering their structures. In this research, PSV was subjected to conjugation with pectin, and changes in physicochemical characteristics and functionalities were determined. The results showed that PSV underwent an unfolding process when conjugated with pectin at a mass ratio of 1 : 2, exposing more hydrophobic groups. Excessive glycosylation induced a refolded structure with a lower surface hydrophobicity and a higher thermal stability. These secondary and tertiary structural changes improved the emulsifying properties of PSV and allowed the production of emulsions with smaller oil droplets. Simultaneously, due to redistribution of phosphate groups, the PPP derived from copolymers exhibited a stronger calcium binding capacity, especially at a mass ratio of 1 : 6, possessing a potential to be utilized in functional foods.


Assuntos
Cálcio/química , Emulsificantes/química , Pectinas/química , Fosfopeptídeos/química , Fosvitina/química , Animais , Galinhas , Gema de Ovo/química , Emulsões/química , Temperatura Alta , Hidrólise
17.
Chembiochem ; 20(6): 770-777, 2019 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-30451361

RESUMO

The sensitivity of Raman optical activity (ROA) towards small conformational changes is explored by tracking the structural changes in an intrinsically disordered protein-phosvitin-induced by different concentrations of crowding agent. It is shown that ROA is capable of tracking small conformational changes involving ß-sheet and α-helical secondary structural properties of the protein. Furthermore, it is indicated that the influences of the crowding agents employed, Ficoll 70 and dextran 70, on the structural properties of phosvitin differ significantly, with the structural changes induced by the presence of Ficoll 70 being more pronounced and already being visible at a lower concentration. The data also suggest that some spectral changes do not arise from a change in the secondary structure of the protein, but are related to differences in interaction between the phosphorylated residues of the protein and the sugar-based crowding agent.


Assuntos
Proteínas Intrinsicamente Desordenadas/química , Fosvitina/química , Dextranos/química , Ficoll/química , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta , Análise Espectral Raman
18.
FEBS J ; 285(24): 4674-4683, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30387551

RESUMO

Egg yolk phosvitins, generated through the fragmentation of vitellogenins (VTGs), are among the most heavily phosphorylated proteins ever described. Despite the early discovery in 1900 that chicken phosvitin is a phosphoprotein and its subsequent employment as an artificial substrate for a number of protein kinases, the identity of the enzyme(s) responsible for its phosphorylation remained a matter of conjecture until present. Here, we provide evidence that phosvitin phosphorylation is catalyzed by a family with sequence similarity 20, member C (Fam20C), an atypical protein kinase recently identified as the genuine casein kinase and responsible for the phosphorylation of many other secreted proteins at residues specified by the S-x-E/pS consensus. Such a conclusion is grounded on the following observations: (a) the levels of Fam20C and phosphorylated VTG rise in parallel upon treatment of zebrafish with oestrogens; (b) zebrafish phosvitin is readily phosphorylated upon coexpression in U2OS cells with Fam20C, but not with its catalytically inactive mutant; (c) a peptide reproducing a stretch of 12 serines, which are phosphorylated in chicken phosvitin despite lacking the C-terminal priming motif S-x-E, is efficiently phosphorylated by both recombinant and native Fam20C. The last finding expands the repertoire of potential targets of Fam20C to include several proteins known to harbor (p-Ser)n clusters not specified by any known kinase consensus.


Assuntos
Caseína Quinase I/metabolismo , Proteínas da Matriz Extracelular/metabolismo , Complexo de Golgi/enzimologia , Peptídeos/metabolismo , Fosfoproteínas/metabolismo , Fosvitina/metabolismo , Sequência de Aminoácidos , Animais , Galinhas , Consenso , Humanos , Fosforilação , Homologia de Sequência , Peixe-Zebra
19.
Food Chem ; 268: 369-377, 2018 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-30064771

RESUMO

In this study, leftover egg yolk granules, a by-product after phosvitin extraction, were evaluated for the physicochemical and functional properties and the results were compared with those of the egg yolk and whole granule with phosvitin. Leftover granule after phosvitin removal accounted for 12.6% of the dried egg yolk and contained 84.5% protein and 7.98% fat. Scanning electron microscopy (SEM) images of leftover granules indicated the dissociation of aggregates of high density lipoprotein-phosvitin complexes. Protein solubility of leftover granules was markedly influenced by pH and sodium chloride (0.5 and 1 M). The apparent viscosity of leftover granule was higher than egg yolk and whole granule. Compared to whole granule, leftover granule had significantly (P < 0.05) superior foaming and emulsifying properties, but, lower than those of egg yolk. These findings are useful for the food industry for utilization of leftover egg yolk granules for the preparation of various food products.


Assuntos
Gema de Ovo/química , Manipulação de Alimentos/métodos , Fosvitina/química , Cloreto de Sódio , Solubilidade , Viscosidade
20.
Food Funct ; 9(9): 4602-4610, 2018 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-30088822

RESUMO

Multiple freeze-thaw (F-T) treatments could modify a protein structure and affect its physicochemical and biological activities. In this work, egg phosvitin (PSV) was subjected to multiple F-T treatments, and the changes in physicochemical and functional properties were investigated. The F-T treatments modified the molecular characteristics of PSV involving a decrease in surface hydrophobicity. Differential scanning calorimetry and scanning electron microscopy showed that PSV underwent denaturation, dissociation and possibly aggregation. Correspondingly, the emulsifying ability of PSV dramatically improved from 1.87 m2 g-1 to 3.70 m2 g-1, 3.25 m2 g-1 and 3.15 m2 g-1 after 3, 6, and 9 F-T cycles, respectively. In parallel, the PSV phosphopeptides (PPP) derived from the F-T treated PSV showed a higher calcium binding capacity and protecting activity against H2O2-induced apoptotic cell death of HepG2 cells, when compared with PPP from native PSV. These results indicated that the F-T treatments have potential to be implemented as a strategy to improve the emulsifying and biological activities of PSV.


Assuntos
Fosfopeptídeos/química , Fosvitina/química , Animais , Apoptose/efeitos dos fármacos , Galinhas , Emulsões/química , Emulsões/farmacologia , Manipulação de Alimentos , Congelamento , Células Hep G2 , Humanos , Fosfopeptídeos/farmacologia , Fosvitina/farmacologia
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