title: Legumin allergens from peanuts and soybeans: effects of denaturation and aggregation on allergenicity.
abstract: Legumin proteins Ara h 3 from peanuts and glycinin from soybeans are increasingly described as important allergens. The stability of an allergen's IgE binding capacity towards heating and digestion is considered an important characteristic for food allergens. We investigated the effects of heating and digestion on the IgE binding of Ara h 3 and glycinin. Both proteins are relatively stable to denaturation, having denaturation temperatures ranging from 70 to 92 degrees C, depending on their quaternary structure and the ionic strength. Aggregates were formed upon heating, which were partly soluble for glycinin. Heating slightly decreased the pepsin digestion rate of both allergens. However, heating did not affect the IgE binding capacity of the hydrolyzates, as after only 10 min of hydrolysis no IgE binding could be detected any more in all samples. Peanut allergen Ara h 1, when digested under equal conditions, still showed IgE binding after 2 h of hydrolysis. Our results indicate that the IgE binding capacity of legumin allergens from peanuts and soybeans does not withstand peptic digestion. Consequently, these allergens are likely unable to sensitize via the gastro-intestinal tract and cause systemic food allergy symptoms. These proteins might thus be less important allergens than was previously assumed.
authors.affiliation: Laboratory of Food Chemistry, Wageningen University, EV Wageningen, The Netherlands.
authors.forename: Evelien L
authors.initials: EL
authors.lastname: van Boxtel
authors.forename: Lambertus A M
authors.initials: LA
authors.lastname: van den Broek
authors.forename: Stef J
authors.initials: SJ
authors.lastname: Koppelman
authors.forename: Harry
authors.initials: H
authors.lastname: Gruppen
mesh_terms: D000485:Allergens / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism; D052179:Antigens, Plant; D010367:Arachis / Q000737:chemistry*; D004355:Drug Stability; D005512:Food Hypersensitivity / Q000097:blood / Q000276:immunology; D005916:Globulins / Q000737:chemistry / Q000276:immunology / Q000378:metabolism; D006358:Hot Temperature; D006801:Humans; D007073:Immunoglobulin E / Q000378:metabolism; D021183:Peanut Hypersensitivity / Q000097:blood / Q000276:immunology; D010434:Pepsin A / Q000378:metabolism; D010940:Plant Proteins / Q000737:chemistry* / Q000276:immunology*; D011489:Protein Denaturation; D020836:Protein Structure, Quaternary; D055314:Seed Storage Proteins; D012639:Seeds / Q000737:chemistry / Q000276:immunology; D030262:Soybean Proteins / Q000737:chemistry / Q000276:immunology / Q000378:metabolism; D013025:Glycine max / Q000737:chemistry*; D013329:Structure-Activity Relationship; D000097793:Legumins
chemical_list: D000485:Allergens; D052179:Antigens, Plant; D005916:Globulins; D007073:Immunoglobulin E; D010434:Pepsin A; D010940:Plant Proteins; D055314:Seed Storage Proteins; D030262:Soybean Proteins; D000097793:Legumins; C118207:allergen Ara h3; C011474:glycinin