Determination of pepsin-susceptible and pepsin-resistant epitopes in native and heat-treated peanut allergen Ara h 1

article



Boxtel, E.L. van

Koppelman, S.J.

Broek, L.A.M. van den

Gruppen, H.
This study was aimed at the determination of the pepsin-susceptible and pepsin-resistant epitopes in native and heat-treated Ara h 1, a major allergen from peanuts. Both the oligomeric structure and the trimeric structure of the allergen were investigated. Under the in vitro conditions applied, oligomeric Ara h 1, either unheated or preheated, was hydrolyzed by pepsin at a lower rate than trimeric Ara h 1. Peptides with relatively high molecular masses were shown to be able to bind IgE, whereas peptides with lower molecular masses (<2 kDa) did not. In these latter fractions, fragments of 15 previously published epitopes of mature Ara h 1 were identified. As a result, these epitopes are not likely responsible for the induction of systemic food allergic reactions to peanuts. Using sequential chymotrypsin digestion, the pepsin-resistant IgE-binding peptides were deduced to contain the previously identified intact epitopes EDWRRPSHQQ (amino acids 50-59) and PRKIRPEG (amino acids 60-67). The presence of four additional earlier published intact epitopes (covering amino acids 6-13, 14-21, 24-31, and 40-47) on the pepsin-resistant peptides could be neither deduced nor ruled out. The two deduced and four possible pepsin-resistant epitopes are all situated in the N-terminal part of Ara h 1, which does not show homology with other vicilin proteins. Consequently, this unique N-terminal part of Ara h 1 is proposed to be responsible for the allergen's ability to induce systemic allergic reactions. © 2008 American Chemical Society.
Chemicals / CAS: chymotrypsin, 9004-07-3, 9014-64-6; immunoglobulin E, 37341-29-0; pepsin A, 9001-75-6; Allergens; Ara h 1 protein, Arachis hypogaea; Chymotrypsin, EC 3.4.21.1; Epitopes; Glycoproteins; Immunoglobulin E, 37341-29-0; Pepsin A, EC 3.4.23.1; Peptide Fragments; Plant Proteins
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Ara h 1EpitopesFood allergyIgE bindingMass spectrometryallergenAra h 1 protein, Arachis hypogaeachymotrypsinepitopeglycoproteinimmunoglobulin Epepsin Apeptide fragmentvegetable proteinamino acid sequencearticlechemistryheathydrolysisimmunologymetabolismmolecular geneticsmolecular weightAllergensAmino Acid SequenceChymotrypsinEpitopesGlycoproteinsHeatHydrolysisImmunoglobulin EMolecular Sequence DataMolecular WeightPepsin APeptide FragmentsPlant ProteinsAraArachis hypogaea
TNO Identifier
240710
Repository link
https://resolver.tno.nl/uuid:c6345b15-a1b2-491b-993e-1ebb1aac7eed
ISSN
00218561
Source
Journal of Agricultural and Food Chemistry, 56(6), pp. 2223-2230.
Pages
2223-2230
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