The Experts below are selected from a list of 756 Experts worldwide ranked by ideXlab platform
Dong U. Ahn - One of the best experts on this subject based on the ideXlab platform.
-
Preparation of phosphopeptides from Phosvitin using the high-temperature and mild pressure pretreatment and enzyme combinations
2020 Iowa State University Animal Industry Report, 2021Co-Authors: Dong U. Ahn, Sun Hee Moon, Xi HuangAbstract:Phosvitin is an excellent source for phosphopeptide production, but it is highly resistant to enzymatic hydrolysis. The high-temperature and mild pressure (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 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 (PPPs) for their subsequent functional characterizations.
-
anti elastase and anti hyaluronidase activity of Phosvitin isolated from hen egg yolk
British Poultry Science, 2020Co-Authors: J H Lee, Dong U. Ahn, S H Moon, Y Hong, Hyun-dong PaikAbstract: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 degrada...
-
Effective Preparation Method of Phosphopeptides from Phosvitin and the Analysis of Peptide Profiles Using Tandem Mass Spectrometry.
Journal of agricultural and food chemistry, 2019Co-Authors: Xi Huang, Sun Hee Moon, Jae-hoon Lee, Hyun-dong Paik, Eun Joo Lee, Byungrok Min, Dong U. AhnAbstract: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.
-
characterization of Phosvitin phosphopeptides using maldi tof mass spectrometry
Animal Industry Report, 2016Co-Authors: Himali Samaraweera, Sun Hee Moon, Dong U. AhnAbstract:Putative phosphopeptides produced from enzymehydrolysis of Phosvitin were identified and characterizedusing MALDI-TOF/MS. Phosvitin was heat-pretreated andthen hydrolyzed using pepsin, thermolysin, and trypsin attheir optimal pH and temperature conditions with or withoutpartial dephosphorylation. Pepsin and thermolysin were noteffective in producing phosphopeptides, but trypsinhydrolysis produced many peptides from Phosvitin: 12peptides, 10 of which were phosphopeptides, were identifiedfrom the trypsin hydrolysate. Twelve peptides were alsoidentified from the trypsin hydrolysate of partiallydephosphorylated Phosvitin, but the number of phosphategroups remaining with the peptides was much smaller thanthose from the trypsin hydrolysate of intact Phosvitin. Thissuggested that the phosphopeptides produced from thepartially dephosphorylated Phosvitin lost most of theirphosphate groups during the dephosphorylation step.Therefore, partial dephosphorylation of Phosvitin beforetrypsin hydrolysis may not be always recommendable inproducing functional phosphopeptides if the phosphategroups play important roles for their functionalities.
-
sequential separation of immunoglobulin y and Phosvitin from chicken egg yolk without using organic solvents
Poultry Science, 2014Co-Authors: Dong U. Ahn, Inwook Choi, Hyunyong Lee, E D N S Abeyrathne, Joo Won SuhAbstract:Abstract A study was conducted to develop a simple sequential separation protocol to separate Phosvitin and IgY from egg yolk without using organic solvents. Egg yolk was diluted with 2 volumes of distilled water (DW), homogenized, and centrifuged. The precipitant was collected and homogenized with 4 volumes of 10% NaCl (wt/vol) in 0.05 N NaOH solution to extract Phosvitin. The pH of the homogenate was adjusted to 4.0 and the precipitate was removed by centrifugation. The supernatant was collected and then heat-treated at 70°C for 30 min and centrifuged to remove impurities. The supernatant containing Phosvitin was collected, had salts removed, and was concentrated and then freeze-dried. The supernatant from the centrifugation of diluted egg yolk was diluted again with 3 volumes of DW, and the precipitate was removed by centrifugation. The resulting supernatant was concentrated using ultrafiltration and then IgY was precipitated using 20% saturated (NH4)2 SO4 + 15% NaCl (wt/vol). The precipitant was collected after centrifugation at 3,400 × g for 30 min at 4°C and dissolved with DW, had salts removed, and then was freeze-dried. The purity of separated Phosvitin and IgY was checked using SDS-PAGE and the proteins were verified using Western blotting. The purity of Phosvitin and IgY was 97.2 and 98.7%, and the yield was 98.7 and 80.9%, respectively. The ELISA results indicated that the activities of separated IgY and Phosvitin were 96.3 and 98.3%, respectively. This study proved that both Phosvitin and IgY can be separated in sequence from egg yolk without using an organic solvent. Also, the method is very simple and has a high potential for scale-up processing.
Marc Anton - One of the best experts on this subject based on the ideXlab platform.
-
Interfacial characteristics of spread films of hen egg yolk Phosvitin at the air-water interface: Interrelation with its charge and aggregation state
Food Hydrocolloids, 2007Co-Authors: Corinne Belhomme, Catherine Guérin-dubiard, Elisabeth David-briand, Marie-hélène Ropers, Marc AntonAbstract:Phosvitin is an egg yolk protein constituted by 50% of serines which are all phosphorylated. Because of this peculiarity, Phosvitin has a high charge density and is known to be one of the most natural cation-binding proteins. In addition, Phosvitin naturally forms aggregates through phosphocalcic bridges in egg yolk. This high charge density, doubled by this capacity to aggregate, limits the adsorption of the protein at oil-water or air-water interfaces. In this work, we investigated the impact of both the charge, by sodium chloride (NaCl) addition, and the aggregation, by calcium chloride addition, on the interfacial properties of Phosvitin. The air-water interfacial activity of the Phosvitin was studied with a Wilhelmy-type film balance and a Brewster angle microscope. In the presence of increasing NaCl concentrations, Phosvitin presents improved interfacial properties and the film formed was more dense. The better adsorption of the Phosvitin is attributed to the charge sc! reening due to NaCl which could permit a higher spreading of the protein at the interface. Concerning the aggregation effect, calcium-Phosvitin aggregates favour the contact between the protein and the interface and act on the interfacial film morphology inducing the formation of a thicker and a more rigid interfacial Phosvitin film.
-
Oil-in-water emulsion properties and interfacial characteristics of hen egg yolk Phosvitin
Food Hydrocolloids, 2006Co-Authors: Oscar Francisco Castellani, Catherine Guérin-dubiard, Elisabeth David-briand, Corinne Belhomme, Marc AntonAbstract:Phosvitin is an egg yolk protein, constituted by 50% of serines, which are all phosphorylated. This singularity makes of Phosvitin one of the most safety natural iron binding molecules. When hen egg yolk is used as emulsifying agent, the adsorption of Phosvitin could alter this iron binding property. Consequently, this work was performed to better understand emulsifying and interfacial properties of Phosvitin in optimal metal binding conditions. We have studied sunflower oil-in-water emulsions of Phosvitin at pH 5 and 6, and ionic strengths of 0.05 and 0.15 M. The oil droplet size, the stability against coalescence and flocculation, the composition of the interfacial protein film and the interfacial activity at model interfaces were analysed. Finally, the capacity of Phosvitin to bind iron when it is anchored at the emulsion interface was investigated. Phosvitin showed satisfactory emulsifying capacity in conditions favouring iron fixation. In these conditions, emulsifying activity is sensitive to pH whereas flocculation is influenced by ionic strength. Coalescence destabilisation is not extended and the interfacial protein film has better characteristics at pH 5. Phosvitin was not efficient to reduce the oil-in-water interfacial tension, although at 0.1 mg/ml the interfacial tension was reduced from 31 mN/m to 15 mN/m. The high iron binding capacity of Phosvitin in solution is kept by interfacial adsorbed Phosvitin. Finally, to explain the poor adsorption efficiency coupled with the suitable emulsifying properties of Phosvitin and the preservation of the iron binding capacity, it is likely that Phosvitin is anchored at the interface only by a tiny terminal portion, presenting the rest of the molecule solvated on the aqueous phase.
-
Influence of physicochemical conditions and technological treatments on the iron binding capacity of egg yolk Phosvitin
Food Chemistry, 2004Co-Authors: Oscar Castellani, Catherine Guérin-dubiard, Elisabeth David-briand, Marc AntonAbstract:Abstract The iron binding capacity of egg yolk Phosvitin was evaluated at different conditions of pH (3.0–7.0) and ionic strength (0.10–0.60). The best value was obtained at pH 6.5 and 0.15 M of ionic strength (115 μg of iron/mg of Phosvitin). For pH values under 3.5, iron fixation was slow and weak. When increasing ionic strength at pH values higher than 5.2, iron binding capacity was weakened. On the contrary, between 5.2 and 3.5 of pH values, the higher the ionic strength, the better the iron fixation. Once iron was fixed in favourable conditions, further acidification does not modify iron binding capacity of Phosvitin. Only the presence of a strong chelating agent could remove iron from Phosvitin. Phosvitin treated by thermal or high pressure methods did not result in aggregation and kept its high iron binding capacity, even at the strongest treatment conditions (90 °C or 600 MPa).
-
egg yolk Phosvitin preparation of metal free purified protein by fast protein liquid chromatography using aqueous solvents
Journal of Chromatography B, 2003Co-Authors: Oscar Castellani, V Martinet, Elisabeth Davidbriand, Catherine Guerindubiard, Marc AntonAbstract:Two chromatographic methods for hen egg yolk Phosvitin purification avoiding organic solvents were evaluated. Hydrophobic interaction and ion-exchange chromatographies were applied to isolated Phosvitin. Hydrophobic interaction chromatography has better capacity than ion-exchange chromatography to fractionate Phosvitin in their different polypeptides, but its protein yield was lower (0.7 vs. 1.7% of egg yolk dry matter). Finally, ion-exchange chromatography was selected and allowed to fractionate Phosvitin polypeptides, including the recovering of phosphoproteins with high electrophoretic mobility: phosvettes. Highly purified (>98%) and free metal protein was obtained in reduced time. Phosvitin polypeptide heterogeneity was evidenced.
Xi Huang - One of the best experts on this subject based on the ideXlab platform.
-
Preparation of phosphopeptides from Phosvitin using the high-temperature and mild pressure pretreatment and enzyme combinations
2020 Iowa State University Animal Industry Report, 2021Co-Authors: Dong U. Ahn, Sun Hee Moon, Xi HuangAbstract:Phosvitin is an excellent source for phosphopeptide production, but it is highly resistant to enzymatic hydrolysis. The high-temperature and mild pressure (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 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 (PPPs) for their subsequent functional characterizations.
-
Effective Preparation Method of Phosphopeptides from Phosvitin and the Analysis of Peptide Profiles Using Tandem Mass Spectrometry.
Journal of agricultural and food chemistry, 2019Co-Authors: Xi Huang, Sun Hee Moon, Jae-hoon Lee, Hyun-dong Paik, Eun Joo Lee, Byungrok Min, Dong U. AhnAbstract: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.
-
phosphorylated serine clusters of Phosvitin plays a crucial role in the regulatory mineralization
International Journal of Biological Macromolecules, 2018Co-Authors: Xiaowei Zhang, Xi HuangAbstract:Abstract Phosphorylation of Phosvitin has been proved to play an important role in the mineralization, but the active region of Phosvitin is still not known yet. Four Phosvitin phosphopeptides (PPPs) were obtained after separating from ion exchange column and desalting from gel filtration, and named as PPP0, PPP1, PPP3 and PPP4, respectively. The effect of PPP on the mineralization was investigated by pH-stat system, Fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscope. SDS-PAGE and circular dichroism were applied to study the composition and the structure of PPP. Results showed that the order of promoting mineralization was as follows: PPP3 > Phosvitin > PPP4 > PPP1 > control > PPP0. PPP0 and PPP1 was not involved in the mineralization, while the structure of PPP4 was too compact to promote mineralization because of its high β-sheet conformation. PPP3, which contained a 10 kDa peptide, is the most effective promoter for mineralization. LTQ-MS/MS results indicated that the phosphorylated serine clusters of Phosvitin was the active region for promoting mineralization.
-
hen egg yolk Phosvitin stimulates osteoblast differentiation in the absence of ascorbic acid
Journal of the Science of Food and Agriculture, 2017Co-Authors: Qingli Liu, Fang Geng, Xi HuangAbstract:Egg yolk Phosvitin, one of the most highly phosphorylated extracellular matrix proteins known in nature, has a strong calcium binding and reducing capacity. Here, we investigated the effects of Phosvitin on osteoblast differentiation and osteogenic gene expression in cultured mouse osteoblastic MC3T3-E1 cells by using alkaline phosphatase activity analysis, alizarin red S staining and real-time PCR assay.; Results: Alkaline phosphatase activity and alizarin red S staining analyses demonstrated no significant difference between differentiating MC3T3-E1 cells cultured in the presence of Phosvitin and those cultured in the presence of ascorbic acid after 21 days of differentiation. Our real-time PCR assay also indicated the two groups were similar in the expression of the osteogenic gene markers, collagen type I, osteocalcin, runt-related transcription factor 2, and bone morphogenetic protein-2.; Conclusion: Our findings indicate that Phosvitin plays a similar role to that of ascorbic acid in osteoblast differentiation and mineralisation. © 2017 Society of Chemical Industry.; © 2017 Society of Chemical Industry.
-
role of phosphorylation of Phosvitin in the phase transformation of mineralization
International Journal of Biological Macromolecules, 2017Co-Authors: Xiaowei Zhang, Xi HuangAbstract:Abstract Phosvitin is a unique highly phosphorylated protein that plays a role in the regulation of mineralization. This study investigated the role of phosphorylation of Phosvitin in the phase transformation of calcium phosphate in the mineralization solution. Partially dephosphorylated Phosvitins (T1, T2, T3 and T4) were prepared with 2.98, 19.46, 43.39 and 71.07% of phosphate released from native Phosvitin, respectively. And their effect on regulating the phase transformation was investigated, the characterization and composition analysis was performed by circular dichroism, Fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy. Results showed that Phosvitin in the acceleration effect of phase transformation was dose-concentration effect by pH-stat titration. With lower dephosphorylation degree of Phosvitin ( 40%), the acceleration effect was enhanced compared to native Phosvitin, in which the β-sheet structure was increased and Phosvitin was partially hydrolyzed to phosphopeptides. The acceleration effect of phase transformation was as follows: T4 > T3 > Phosvitin > T1 > T2 > Control. This study clearly demonstrated that phosphorylation of Phosvitin played an important role in the regulation of mineralization.
Jiandong Ren - One of the best experts on this subject based on the ideXlab platform.
-
Phosvitin derived phospho peptides show better osteogenic potential than intact Phosvitin in mc3t3 e1 osteoblastic cells
Nutrients, 2020Co-Authors: Subhadeep Chakrabarti, Jiandong RenAbstract: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.
-
Phosvitin and its hydrolysate promote differentiation and inhibit tnf ɑ induced inflammation in mc3t3 e1 cells via erk and akt pathways
Journal of Functional Foods, 2019Co-Authors: Jiandong Ren, Subhadeep ChakrabartiAbstract:Abstract Phosvitin and its hydrolysate were reported to show antioxidant, anti-inflammation and antimicrobial activities. Given the critical role of inflammation on bone health, the work was designed to study the effects of Phosvitin and its hydrolysate on osteoblast differentiation and inflammation in osteoblastic (MC3T3-E1) cells. Both Phosvitin and its hydrolysate promoted osteoblast differentiation by upregulating expression of runt-related transcription factor 2, alkaline phosphatase (by Phosvitin hydrolysate), osteocalcin production (by Phosvitin) and collagen synthesis. They also inhibited TNF-ɑ induced inflammation by reducing the production of regulated on activation, normal T cell expressed and secreted and monocyte chemoattractant protein-1, which are crucial for recruiting osteoclast progenitor and maintaining osteoclast functions, and cyclooxygenase-2, a proinflammatory protein. Adding Phosvitin and its hydrolysate activated both extracellular signal–regulated kinases (ERK) and protein kinase B (AKT) signaling pathways, indicating that both Phosvitin and its hydrolysate promote osteoblast differentiation and exert antiinflammation effects via ERK and AKT pathways.
-
preparation and characterization of phosphopeptides from egg yolk Phosvitin
Journal of Functional Foods, 2015Co-Authors: Jiandong Ren, Marina OffengendenAbstract:Abstract Egg yolk Phosvitin is a highly phosphorylated protein. Its derived phosphopeptides may help improve bone and dental health, in addition to its antioxidant and anti-inflammatory activities. However, the structural information of these peptides was poorly characterized. In this study, we aimed to prepare Phosvitin phosphopeptides by enzymatic hydrolysis and characterize the peptide sequences and phosphorylation by LC–MS/MS. Phosvitin was partially dephosphorylated by 0.2 M NaOH prior to pancreatin hydrolysis. The degree of hydrolysis was 12.9% and the peptide recovery was 6.1% (based on egg yolk). The N/P value of 3.9 was comparable or lower than purified casein phosphopeptides, which ranged from 6 to 18. After anion exchange chromatography, 32 peptides were identified from three Phosvitin domains: AEFGTEPDAKTSSSSSSASSTATSSSSSSASSPN (PV 1–34), KPMDEEENDQV (PV 37–47) and SGHLEDDSSSSSSSSVLSKIWG (PV 190–211). These peptides contain up to 10 phosphate groups.
-
thermal aided Phosvitin extraction from egg yolk
Journal of the Science of Food and Agriculture, 2015Co-Authors: Jiandong RenAbstract:BACKGROUND Phosvitin is the principal phosphoprotein in egg yolk and has great potential for use as a functional food ingredient in improving bone health. This study reports a thermal-aided extraction method without using organic solvents or non-food-compatible chemicals. RESULTS Egg yolk was two times diluted with water and then extracted by 100 g L−1 NaCl. Effects of pH and heating temperature on the extract were examined. The Phosvitin purity increased from 75.7% at pH 8.0 to 80.1% at pH 5.0 and then started to decrease, but the yield decreased at decreasing pHs. The Phosvitin purity increased at increasing temperature up to 90 °C and then started to decrease at 95 °C, while the yield increased from 70 to 80 °C and then started to decline at 85 °C. CONCLUSION A purity of 88.0% and a yield of 23.5 g kg−1 yolk dry matter were obtained at 90 °C. The purity and yield were comparable to or higher than those of previously methods. The method developed in this study is simple, including mainly two steps, i.e. water dilution of egg yolk and NaCl extraction with heating, and can be scaled up for industrial production. © 2015 Society of Chemical Industry
-
preparation of high purity egg Phosvitin using anion exchange chromatography
Food Chemistry, 2014Co-Authors: Jiandong RenAbstract:Egg yolk Phosvitin serves as a warehouse to provide metal ions for embryo development. It is significant for mineral metabolism study and also of great potential to be developed into functional foods with mineral absorption promoting ability. In this study, Phosvitin was first extracted from yolk granules using 10% NaCl, dialysed and then adjusted to various pHs to remove impurities. The purity of Phosvitin extracts was increased from 54.5% to 63.7% at decreasing pH from 8.0 to 5.5, and started to decrease afterwards. Both the yield and recovery were significantly decreased at decreasing pHs, especially at pHs close to its pI (pH 4.0), indicating the occurrence of co-precipitation of Phosvitin with HDL. The extract prepared at pH 8.0 showed the highest recovery of 82.7%; its purity was increased from 54.5% to 97.1% by anion exchange chromatography, with a recovery of 42.0%. This simple method could be scaled up for industrial production.
Xiaowei Zhang - One of the best experts on this subject based on the ideXlab platform.
-
phosphorylated serine clusters of Phosvitin plays a crucial role in the regulatory mineralization
International Journal of Biological Macromolecules, 2018Co-Authors: Xiaowei Zhang, Xi HuangAbstract:Abstract Phosphorylation of Phosvitin has been proved to play an important role in the mineralization, but the active region of Phosvitin is still not known yet. Four Phosvitin phosphopeptides (PPPs) were obtained after separating from ion exchange column and desalting from gel filtration, and named as PPP0, PPP1, PPP3 and PPP4, respectively. The effect of PPP on the mineralization was investigated by pH-stat system, Fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscope. SDS-PAGE and circular dichroism were applied to study the composition and the structure of PPP. Results showed that the order of promoting mineralization was as follows: PPP3 > Phosvitin > PPP4 > PPP1 > control > PPP0. PPP0 and PPP1 was not involved in the mineralization, while the structure of PPP4 was too compact to promote mineralization because of its high β-sheet conformation. PPP3, which contained a 10 kDa peptide, is the most effective promoter for mineralization. LTQ-MS/MS results indicated that the phosphorylated serine clusters of Phosvitin was the active region for promoting mineralization.
-
role of phosphorylation of Phosvitin in the phase transformation of mineralization
International Journal of Biological Macromolecules, 2017Co-Authors: Xiaowei Zhang, Xi HuangAbstract:Abstract Phosvitin is a unique highly phosphorylated protein that plays a role in the regulation of mineralization. This study investigated the role of phosphorylation of Phosvitin in the phase transformation of calcium phosphate in the mineralization solution. Partially dephosphorylated Phosvitins (T1, T2, T3 and T4) were prepared with 2.98, 19.46, 43.39 and 71.07% of phosphate released from native Phosvitin, respectively. And their effect on regulating the phase transformation was investigated, the characterization and composition analysis was performed by circular dichroism, Fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy. Results showed that Phosvitin in the acceleration effect of phase transformation was dose-concentration effect by pH-stat titration. With lower dephosphorylation degree of Phosvitin ( 40%), the acceleration effect was enhanced compared to native Phosvitin, in which the β-sheet structure was increased and Phosvitin was partially hydrolyzed to phosphopeptides. The acceleration effect of phase transformation was as follows: T4 > T3 > Phosvitin > T1 > T2 > Control. This study clearly demonstrated that phosphorylation of Phosvitin played an important role in the regulation of mineralization.
-
Calcium binding characteristics and structural changes of Phosvitin.
Journal of inorganic biochemistry, 2016Co-Authors: Xiaowei Zhang, Fang Geng, Xi HuangAbstract:Phosvitin is a unique highly phosphorylated protein that plays a role in the regulation of calcification. We conducted a comprehensive study of the chemical, thermodynamic and structural aspects of the interaction of Phosvitin with calcium ions using a calcium ion selective electrode (ISE), isothermal titration calorimetry (ITC), circular dichroism spectrum (CD) and fluorescence spectroscopy, respectively. The results showed that under neutral and alkaline conditions, distinct high affinity and low affinity binding modes existed in the interaction between Phosvitin and calcium. The high affinity association constant was approximately 10(4)mol(-1), while the binding sites contained nearly 30mol of calcium per mole of Phosvitin. This reaction was driven by enthalpy. The unordered and β-turn conformations of Phosvitin increased, while the β-sheet conformation decreased. The main interaction forces were electrostatic force, hydrogen bonds or van der Waals force. The low affinity association constant and binding sites were not constant, as many calcium ions were sequestered by Phosvitin. The binding reaction was driven by entropy, and the β-sheet conformation of Phosvitin increased while the unordered conformation decreased. The main interaction force was hydrophobic force. However, under acidic conditions, the interaction between Phosvitin and calcium was an entropy-driven endothermic reaction, and the main interaction force was weak hydrophobic force. This calcium-binding characteristic of Phosvitin may play a specific role in its biological function.
-
acceleration of the initial phase transformation of mineralization by Phosvitin
Journal of Crystal Growth, 2015Co-Authors: Xiaowei Zhang, Fang Geng, Xi HuangAbstract:Abstract Phosvitin has a similar structure and similar properties to the phosphorylated proteins that play an important role in biomineralization, suggesting that Phosvitin may have similar regulation properties. This study investigated the effect of Phosvitin on regulating the phase transformation of the mineral calcium phosphate in a biomimetic mineralization solution; the characterization techniques used were Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy and fluorescence spectroscopy. The results clearly demonstrated that Phosvitin significantly promotes the initiation of phase transformation, accelerated the transformation process and shortened the transformation time from 6 to 0.5 h. Phosvitin was involved in the phase transformation and incorporated into or strongly absorbed on the mineral, as evidenced by the protein peaks observed in the FTIR spectra and XRD patterns. The effects of the substrate-addition sequence on the phase transformation demonstrated that the Phosvitin-Ca 2+ interaction played a key role in the regulation of mineralization. Compared with those for BSA, the results revealed that the role of Phosvitin in mineralization is closely associated with its high level of phosphorylation. This study provides useful information about using Phosvitin as a potential candidate for biomaterials.
-
Phosvitin phosphorus is involved in chicken embryo bone formation through dephosphorylation
Poultry Science, 2014Co-Authors: Fang Geng, Xi Huang, Xiaowei ZhangAbstract:Abstract The aim of this study was to investigate the role of Phosvitin in bone formation in chicken embryos. The yolk P content, P/N ratio and secondary structure of Phosvitin, alkaline phosphatase (ALP) activity of the tibia, and body length were determined during incubation. A high correlation was found between the phosphate group content of Phosvitin and both secondary structure and bone metabolism (ALP activity in the tibia, body length). The ALP activity and body length growth slightly lagged behind changes in the P/N ratio and the secondary structure of Phosvitin. The phosphate content of Phosvitin decreased, the γ-random coil and β-turn gradually transformed into α-helixes, and the secondary structure of protein tended to become more orderly; these changes mainly occurred on d 13 to 16. Bone formation of the chicken embryos occurred primarily on d 14 to 18, whereas ALP activity and body length growth increased substantially. The results indicate that Phosvitin P is involved in chicken embryo bone formation through dephosphorylation.
