title: Oxidative modification of a proline-rich gliadin peptide.
abstract: Prolamins are proline-rich proteins occurring in cereal grains. Prolamins of wheat, barley and rye, or gluten protein, can cause coeliac disease in individuals not tolerating gluten. Degrading harmful prolamins can reduce their toxicity. A model peptide sequenced in α-gliadin, 33-mer (LQLQPFPQPQLPYPQPQLPYPQPQLPYPQPQPF), was chosen for our study. The metal-catalysed oxidation of 33-mer was studied, instead of enzymatic hydrolysis. Peptide 33-mer was treated in several oxidative systems. Iron-catalysed hydrogen peroxide-induced oxidation showed the greatest modification of 33-mer. Carbonyl groups and dityrosine cross-links were readily formed. At best, the immunological activity of 33-mer was reduced to 18% of its initial level after 24h of oxidation. Oxidative treatment can be further applied for the modification of cereal prolamin proteins, since it appears to be a potential alternative for reduction of coeliac immunological activities in gluten proteins.
authors.affiliation: Department of Food and Environmental Sciences, University of Helsinki, P.O. Box 66, Agnes Sjörbergin katu 2, FI-00014 Helsinki, Finland. xin.huang@helsinki.fi
authors.forename: Xin
authors.initials: X
authors.lastname: Huang
authors.forename: Päivi
authors.initials: P
authors.lastname: Kanerva
authors.forename: Hannu
authors.initials: H
authors.lastname: Salovaara
authors.forename: Jussi
authors.initials: J
authors.lastname: Loponen
authors.forename: Tuula
authors.initials: T
authors.lastname: Sontag-Strohm
mesh_terms: D005903:Gliadin / Q000737:chemistry*; D010084:Oxidation-Reduction; D010455:Peptides / Q000737:chemistry*; D055315:Prolamins / Q000737:chemistry; D011392:Proline / Q000737:chemistry*
chemical_list: D010455:Peptides; D055315:Prolamins; D005903:Gliadin; D011392:Proline
keywords: Coeliac disease; Degradation; Dityrosine; ELISA; Fenton reaction; Gliadin; Proline; Protein oxidation