Purification of Parvalbumin from Carp: A Protocol That Avoids Heat Treatment

Parvalbumin from carp, a major allergen,was purified to homogeneity using ion exchange chromatography and size exclusion chromatography (estimated purity \u3e 95% to 98% based on SDS-PAGE and native PAGE) with a yield of 318 mg, and a number of basic biochemical characteristics were determined. The identity was confirmed by peptide-mass fingerprinting, and IgE-binding was demonstrated. The UV/Vis absorbance spectra were explained using the previously published amino acid sequences. Far UV-CD spectroscopy was used to confirm the folding character of parvalbumin. We conclude that parvalbumin from carp can be purified on a comparatively large (hundreds of milligrams) scale using a purification protocol that does not include denaturing steps. The purified protein resembles biochemical characteristics as were earlier published for carp parvalbumin, that is, a molecular weight of approximately 12 kDa, amino acid sequence identity and a secondary structure containing α-helices and β-structures. The described method provides a yield sufficient to produce and characterize antibodies to construct immunochemical methods to detect parvalbumin in food as well as for use as a standard calibrator for such assays. Practical Application: Parvalbumin is a major allergen from fish. Here,we have purified a comparatively large quantity from carp that can be used to develop antisera for use in an assay method to detect fish allergens

Incorporation of Mesoporous Silica Particles in Gelatine Gels: Effect of Particle Type and Surface Modification on Physical Properties

The aim of this work was to investigate the impact of mesoporous silica particles (MSPs) on the physicochemical properties of filled protein gels. We have studied the effect of the addition of different mesoporous silica particles, either bare or functionalized with amines or carboxylates, on the physical properties of gelatine gels (5% w/v). Textural properties of the filled gels were investigated by uniaxial compression, while optical properties were investigated by turbidity. The MSPs were characterized with the objective of correlating particle features with their impact on the corresponding filled-gel properties. The addition of MSPs (both with and without functionalization) increased the stiffness of the gelatine gels. Furthermore, functionalized MSPs showed a remarkable increase in the strength of the gels and a slight reduction in the brittleness of the gels, in contrast with nonfunctionalized MSPs which showed no effect on these two properties. The turbidity of the gels was also affected by the addition of all tested MSPs, showing that the particles that formed smaller aggregates resulted in a higher contribution to turbidity. MSPs are promising candidates for the development of functional food containing smart delivery systems, also being able to modulate the functionality of protein gels.We gratefully acknowledge the financial support from the Ministerio de Economia y Competitividad (projects AGL2012-39597-C02-01, AGL2012-39597-C02-02, and MAT2012-38429-C04-01) and the Generalitat Valenciana (project PROMETEO/2009/016). E.P.-E. is grateful to the Ministerio de Ciencia e Innovacion for his grant (AP2008-00620). Saskia de Jong (NIZO food research) is acknowledged for assistance during CLSM observations and rheology interpretation.Pérez-Esteve, É.; Oliver Hernández, L.; García López, L.; Nieuwland, M.; De Jongh, HHJ.; Martínez-Máñez, R.; Barat Baviera, JM. (2014). Incorporation of Mesoporous Silica Particles in Gelatine Gels: Effect of Particle Type and Surface Modification on Physical Properties. Langmuir. 30(23):6970-6979. https://doi.org/10.1021/la501206fS69706979302

Digestibility and IgE-Binding of Glycosylated Codfish Parvalbumin

Food-processing conditions may alter the allergenicity of food proteins by different means. In this study, the effect of the glycosylation as a result of thermal treatment on the digestibility and IgE-binding of codfish parvalbumin is investigated. Native and glycosylated parvalbumins were digested with pepsin at various conditions relevant for the gastrointestinal tract. Intact proteins and peptides were analysed for apparent molecular weight and IgE-binding. Glycosylation did not substantially affect the digestion. Although the peptides resulting from digestion were relatively large (3 and 4 kDa), the IgE-binding was strongly diminished. However, the glycosylated parvalbumin had a strong propensity to form dimers and tetramers, and these multimers bound IgE intensely, suggesting stronger IgE-binding than monomeric parvalbumin. We conclude that glycosylation of codfish parvalbumin does not affect the digestibility of parvalbumin and that the peptides resulting from this digestion show low IgEbinding, regardless of glycosylation. Glycosylation of parvalbumin leads to the formation of higher order structures that are more potent IgE binders than native, monomeric parvalbumin. Therefore, food-processing conditions applied to fish allergen can potentially lead to increased allergenicity, even while the protein’s digestibility is not affected by such processing

Supplementary data for the article: Apostolovic, D.; Stanic-Vucinic, D.; De Jongh, H. H. J.; De Jong, G. A. H.; Mihailovic, J.; Radosavljevic, J.; Radibratovic, M.; Nordlee, J. A.; Baumert, J. L.; Milcic, M.; et al. Conformational Stability of Digestion-Resistant Peptides of Peanut Conglutins Reveals the Molecular Basis of Their Allergenicity. Scientific Reports 2016, 6. https://doi.org/10.1038/srep29249

Supplementary material for: [https://doi.org/10.1038/srep29249]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2273

Supplementary data for the article: Apostolovic, D.; Stanic-Vucinic, D.; De Jongh, H. H. J.; De Jong, G. A. H.; Mihailovic, J.; Radosavljevic, J.; Radibratovic, M.; Nordlee, J. A.; Baumert, J. L.; Milcic, M.; et al. Conformational Stability of Digestion-Resistant Peptides of Peanut Conglutins Reveals the Molecular Basis of Their Allergenicity. Scientific Reports 2016, 6. https://doi.org/10.1038/srep29249

Supplementary material for: [https://doi.org/10.1038/srep29249]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2273

The protein structure determines the sensitizing capacity of Brazil nut 2S albumin (\u3ci\u3eBer e1\u3c/i\u3e) in a rat food allergy model

It is not exactly known why certain food proteins are more likely to sensitize. One of the characteristics of most food allergens is that they are stable to the acidic and proteolytic conditions in the digestive tract. This property is thought to be a risk factor in allergic sensitization. The purpose of the present study was to investigate the contribution of the protein structure of 2S albumin (Ber e1), a major allergen from Brazil nut, on the sensitizing capacity in vivo using an oral Brown Norway rat food allergy model. Disulphide bridges of 2S albumin were reduced and alkylated resulting in loss of protein structure and an increased pepsin digestibility in vitro. Both native 2S albumin and reduced/alkylated 2S albumin were administered by daily gavage dosing (0.1 and 1 mg) to Brown Norway rats for 42 days. Intraperitoneal administration was used as a positive control. Sera were analysed by ELISA and passive cutaneous anaphylaxis. Oral exposure to native or reduced/alkylated 2S albumin resulted in specific IgG1 and IgG2a responses whereas only native 2S albumin induced specific IgE in this model, which was confirmed by passive cutaneous anaphylaxis. This study has shown that the disruption of the protein structure of Brazil nut 2S albumin decreased the sensitizing potential in a Brown Norway rat food allergy model, whereas the immunogenicity of 2S albumin remained preserved. This observation may open possibilities for developing immunotherapy for Brazil nut allergy