Abstract
Coeliac disease (CD) is triggered by the ingestion of gluten proteins from wheat, rye, and barley. The 33-mer peptide from α2-gliadin has frequently been described as the most important CD-immunogenic sequence within gluten. However, from more than 890 published amino acid sequences of α-gliadins, only 19 sequences contain the 33-mer. In order to make a precise assessment of the importance of the 33-mer, it is necessary to elucidate which wheat species and cultivars contain the peptide and at which concentrations. This paper presents the development of a stable isotope dilution assay followed by liquid chromatography tandem mass spectrometry to quantitate the 33-mer in flours of 23 hexaploid modern and 15 old common (bread) wheat as well as two spelt cultivars. All flours contained the 33-mer peptide at levels ranging from 91–603 μg/g flour. In contrast, the 33-mer was absent (<limit of detection) from tetra- and diploid species (durum wheat, emmer, einkorn), most likely because of the absence of the D-genome, which encodes α2-gliadins. Due to the presence of the 33-mer in all common wheat and spelt flours analysed here, the special focus in the literature on this most immunodominant peptide seems to be justified.
Highlights
Deutsche Forschungsanstalt für Lebensmittelchemie, Leibniz Institut, Lise-Meitner-Straße 34, D-85354 Freising, Germany
The present study is the first to establish a stable isotope dilution assay (SIDA) combined with targeted LC-MS/MS for the quantitative determination of the immunodominant 33-mer peptide in wheat flours
The UniProtKB database had only 19 out of 897 entries for α-gliadin sequences from Triticinae containing the 33-mer with an identity of 100%, all 40 analysed modern and old common wheat and spelt cultivars contained the immunodominat 33-mer peptide (51 flour samples in total, because several flours were available from different harvest years)
Summary
Deutsche Forschungsanstalt für Lebensmittelchemie, Leibniz Institut, Lise-Meitner-Straße 34, D-85354 Freising, Germany. The high relevance of the 33-mer is reflected by the production of two monoclonal antibodies (A1 und G12) against the 33-mer peptide[18]. These are used in commercially available enzyme-linked immunosorbent assays. The aim of the present study was to develop a stable isotope dilution assay (SIDA) combined with targeted liquid chromatography tandem mass spectrometry (LC-MS/MS) for the quantitative determination of the 33-mer. The amount of 33-mer was determined in 57 samples of different wheat species from around the world (Table 1), including hexaploid common wheat (T. aestivum) and spelt The amount of 33-mer was determined in 57 samples of different wheat species from around the world (Table 1), including hexaploid common wheat (T. aestivum) and spelt (T. aestivum ssp. spelta), tetraploid durum wheat (T. turgidum durum) and emmer (T. turgidum dicoccum), and diploid einkorn (T. monococcum) to make a precise assessment of the importance of this peptide associated with CD
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
