Insights into proteolytic processing of the major peanut allergen Ara h 2 by endogenous peanut proteases

• Published in: Journal of the science of food and agriculture 2010-08, Vol.90 (10), p.1702-1708
• Main Authors: Radosavljevic, Jelena, Dobrijevic, Dragana, Jadranin, Milka, Blanusa, Milan, Vukmirica, Jelena, Cirkovic Velickovic, Tanja
• Format: Article
• Language: English
• Subjects: 2S Albumins, Plant - chemistry; 2S Albumins, Plant - isolation & purification; 2S Albumins, Plant - metabolism; Allergens - chemistry; Allergens - isolation & purification; Allergens - metabolism; Antigens, Plant - chemistry; Antigens, Plant - isolation & purification; Antigens, Plant - metabolism; Ara h 2; Ara h 6; Arachis - chemistry; Arachis hypogaea; Biological and medical sciences; Dipeptides; Food allergies; food allergy; Food industries; Food science; Fundamental and applied biological sciences. Psychology; Gene expression; General aspects; Glycoproteins - chemistry; Glycoproteins - isolation & purification; Glycoproteins - metabolism; Hydrolysis; IgE binding; Immunoglobulin E; Immunoglobulins; Isomerism; Methods of analysis, processing and quality control, regulation, standards; Peanuts; Peptide Hydrolases - metabolism; Peptides; Plant Extracts - chemistry; Plant Extracts - metabolism; Plant Proteins - chemistry; Plant Proteins - isolation & purification; Plant Proteins - metabolism; Proteases; proteolysis; Tyrosine
• ISSN: 0022-5142; 1097-0010
• DOI: 10.1002/jsfa.4005

BACKGROUND: The major peanut allergens are Ara h 1, Ara h 2 and Ara h 6. Proteolytic processing has been shown to be required for the maturation process of Ara h 6. The aim of this study was to examine whether Ara h 2 undergoes proteolytic processing and, if so, whether proteolytic processing influences its ability to bind human immunoglobulin E (IgE). RESULTS: Ara h 2 isolated from peanut extract under conditions of protease inhibition revealed a single additional peak for its two known isoforms (Ara h 2.01 and Ara h 2.02), corresponding to a C‐terminally truncated form lacking a dipeptide (RY). Ara h 2 isolated in the absence of protease inhibition, however, yielded two additional peaks, identified as C‐terminally truncated forms lacking either a dipeptide (RY) or a single tyrosine residue. The IgE‐binding capacity of the Ara h 2 truncated forms was not altered. CONCLUSION: Ara h 2 undergoes proteolytic processing by peanut proteases that involves C‐terminal removal of a dipeptide. Hence Ara h 2 isolated from peanut extract is a complex mixture of two isoforms expressed by different genes, Ara h 2.01 and Ara h 2.02, as well as truncated forms generated by the proteolytic processing of these isoforms. Copyright © 2010 Society of Chemical Industry