Peanut allergen Ara h 3: isolation from peanuts and biochemical characterization.
BACKGROUND
Peanut allergen Ara h 3 has been the subject of investigation for the last few years. The reported data strongly depend on recombinant Ara h 3, since a purification protocol for Ara h 3 from peanuts was not available.


METHODS
Peanut allergen Ara h 3 (glycinin), was purified and its posttranslational processing was investigated. Its allergenic properties were determined by studying IgE binding characteristics of the purified protein.


RESULTS
Ara h 3 consists of a series of polypeptides ranging from approximately 14 to 45 kDa that can be classified as acidic and basic subunits, similar to the subunit organization of soy glycinin. N-terminal sequences of the individual polypeptides were determined, and using the cDNA deduced amino-acid sequence, the organization into subunits was explained by revealing posttranslational processing of the different polypeptides. IgE-binding properties of Ara h 3 were investigated using direct elisa and Western blotting with sera from peanut-allergic individuals. The basic subunits, and to a lesser extent the acidic subunits, bind IgE and may act as allergenic peptides.


CONCLUSIONS
We conclude that peanut-derived Ara h 3, in contrast to earlier reported recombinant Ara h 3, resembles, to a large extent, the molecular organization typical for proteins from the glycinin family. Furthermore, posttranslational processing of Ara h 3 affects the IgE-binding properties and is therefore an essential subject of study for research on the allergenicity of Ara h 3.
Koppelman
S J
SJ
TNO Nutrition and Food Research Institute, Zeist, The Netherlands.
Knol
E F
EF
Vlooswijk
R A A
RA
Wensing
M
M
Knulst
A C
AC
Hefle
S L
SL
Gruppen
H
H
Piersma
S
S
D000485:Allergens / Q000737:chemistry* / Q000276:immunology / Q000302:isolation & purification; D000595:Amino Acid Sequence; D052179:Antigens, Plant; D010367:Arachis / Q000276:immunology*; D002152:Calorimetry, Differential Scanning; D002852:Chromatography, Ion Exchange; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D015151:Immunoblotting; D007073:Immunoglobulin E / Q000276:immunology; D021183:Peanut Hypersensitivity / Q000276:immunology; D055314:Seed Storage Proteins
D000485:Allergens; D052179:Antigens, Plant; D055314:Seed Storage Proteins; C118207:allergen Ara h3; D007073:Immunoglobulin E