title: Improvement of digestibility, reduction in allergenicity, and induction of oral tolerance of wheat gliadin by deamidation.
abstract: Wheat gliadin was deamidated by using a cation-exchange resin in the presence or absence of added cysteine, with the change in digestibility being measured. The allergenicity of the gliadin was evaluated by using sera from patients RAST-positive to wheat. Gliadin-specific IgE was measured after the gliadin had been orally administered to rats. The addition of cysteine before the treatment with a cation exchanger effectively increased the deamidation level of gliadin. Deamidated gliadin showed higher solubility than the undeamidated form. There was no difference in the peptic digestibility of the gliadin, whereas deamidation enhanced the pancreatic digestibility in vitro and the digestibility in the mouse stomach in vivo. Deamidation of gliadin reduced its reactivity toward the sera of patients with wheat allergy. Rats administered with deamidated gliadin showed suppressed elevation of the gliadin-specific IgE level.
authors.affiliation: Department of Agricultural and Biological Chemistry, Nihon University, Fujisawa-Shi, Japan. kumagai@brs.nihon-u.ac.jp
authors.forename: Hitomi
authors.initials: H
authors.lastname: Kumagai
authors.forename: Akihiro
authors.initials: A
authors.lastname: Suda
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Sakurai
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Kumagai
authors.forename: Soichi
authors.initials: S
authors.lastname: Arai
authors.forename: Naoko
authors.initials: N
authors.lastname: Inomata
authors.forename: Zenro
authors.initials: Z
authors.lastname: Ikezawa
mesh_terms: D000577:Amides / Q000737:chemistry*; D000818:Animals; D002852:Chromatography, Ion Exchange; D004064:Digestive System / Q000378:metabolism; D004798:Enzymes / Q000737:chemistry; D005512:Food Hypersensitivity / Q000276:immunology*; D005903:Gliadin / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007073:Immunoglobulin E / Q000032:analysis; D007074:Immunoglobulin G / Q000032:analysis; D051379:Mice; D008807:Mice, Inbred BALB C; D010194:Pancreatin / Q000737:chemistry; D010434:Pepsin A / Q000737:chemistry; D011492:Protein Hydrolysates / Q000737:chemistry / Q000276:immunology; D011817:Rabbits; D012995:Solubility; D014908:Triticum / Q000737:chemistry*
chemical_list: D000577:Amides; D004798:Enzymes; D007074:Immunoglobulin G; D011492:Protein Hydrolysates; D007073:Immunoglobulin E; D010194:Pancreatin; D005903:Gliadin; D010434:Pepsin A