Identification of the three major coeliac immunoreactive proteins and one α‐amylase inhibitor from oat endosperm

Abstract

Six chloroform/mcthanol-solubl¢ proteins from oat endosperm (Avena saliva) have been isolated and characterized by a purification procedure based on extraction with volatile solvents, followed by reversed-phase high performan~ liquid chromatography. Three of these proteins, with an assessed mol~ular weight of 25,000, 27,000 and 32,000 Da, respectively, have been identified by immunoblotting using ¢oeliac sere, as the major co¢liac serum leA-binding components of oat endosperm. The N-terminal amino acid sequence of these proteins indicates that they correspond to oh., 74, and 7a avenins, respectively. We have tentatively named them 'coeliac immunoreactive proteins'. Another chloroform/methanol oat component shows weak g-amylase inhibitory activity and exhibits strong homology (60% identity) at the N-tgrmin~ with the g-amylase inhibitor from ragi (Eleusilze coracana).

Celiac disease, gluten-free diet, and oats

“…Baker and Read 34 documented at the same time the very different approach to oats as part of the GFD in 15 centers located in England, Scotland, and Ireland. It is also important to note the isolation of celiac immunoreactive proteins from oat endosperm by Rocher et al 35 These proteins correspond to alpha2, gamma4, and gamma3 avenins and are the major celiac serum IgA-binding components of oat endosperm.…”

Protein Profiles of Cereals and Pseudocereals Determined by Two-Dimensional Gel Electrophoresis

“…Then, focussing on the gluten fraction, as it is the major trigger for celiac disease, we separated proteins with a basic pI over a narrow pH range of pH 6-11. Putative identifications of proteins were obtained using current literature for each type of crop (Rocher et al, 1992;Varjonen et al, 1994;Rocher et al, 1996;James et al, 1997;Aalberse, 2000;Skylas et al, 2000;Finnie et al, 2002;Gellrich et al, 2003;Bak-Jensen et al, 2004;Østergaard et al, 2004;Perrocheau et al, 2005;Anderson and Wieser, 2006;Akagawa et al, 2007;Dupont et al, 2011;Londono et al, 2013;Vensel et al, 2014;Guo et al, 2016;Klubicová et al, 2016;Malalgoda and Simsek, 2017;Nałęcz et al, 2017;Zhou et al, 2018).…”

“…2) which corresponded to trypsin/alpha-amylase inhibitor proteins. Rocher et al (Rocher et al, 1992) identified three major avenins, which react with celiac sera and that they called oat "celiac immunoreactive proteins" (CIP), as well as one alpha amylase inhibitor from oat endosperm, which showed a significant homology (60-80% of identity) with the alpha amylase inhibitor from ragi, as well as with the two probable alpha amylase inhibitor from rice and barley. Avenin-A (CIP-1), which belongs to the gliadin/glutenin family and causes allergic reaction in human and are one of the cause of CD.…”

β Structure motif recognition by anti‐gliadin antibodies in coeliac disease

“…Likewise, human AGA can in principle cross‐react either with large molecules containing both specific linear or β‐turn motifs, or with peptides showing a low degree of sequence identity, provided they are rich in β‐turn moiety. This could explain why all coeliac sera react with gliadins, hordeins [18–20], secalins [21]and avenins [22]regardless whether the coeliac patient has consumed wheat, barley, rye or oats in the diet.…”