A soybean G2 glycinin allergen. 1. Identification and characterization.
BACKGROUND
Multiple allergens have been documented in soybean extracts. IgE from individuals allergic to soybeans, but not to peanut, was shown by immunoblot analysis to bind to proteins with a molecular weight of approximately 21 kD. These findings suggested that unique proteins in soybeans might be responsible for soybean allergic reactivity. The objective of the present study was to identify unique proteins in soybean extracts that bind to specific IgE from soybean-sensitive individuals, and to characterize the allergen using physicochemical methods and IgE binding.


METHODS
Two-dimensional and preparative SDS-PAGE/IgE immunoblot analysis was used to identify a 22-kD soybean-specific allergen from crude soybean extracts. N-terminal sequence analysis was used to determine the identification of the protein binding IgE from soybean-sensitive individuals.


RESULTS
IgE immunoblot and amino acid sequence analysis identified the 22-kD protein as a member of the G2 glycinin soybean protein family. Further investigation revealed that the IgEs reacted with basic chains from each member of the glycinin family of soybean storage proteins.


CONCLUSIONS
Each of the subunits from glycinin, the storage protein that is the most prevalent component of soybean, are major allergens.
Helm
R M
RM
Department of Pediatrics, University of Arkansas for Medical Sciences, Arkansas Children's Nutrition Center, Little Rock, AR 72202-3591, USA.
Cockrell
G
G
Connaughton
C
C
Sampson
H A
HA
Bannon
G A
GA
Beilinson
V
V
Livingstone
D
D
Nielsen
N C
NC
Burks
A W
AW
D000485:Allergens / Q000737:chemistry / Q000276:immunology*; D000595:Amino Acid Sequence; D004591:Electrophoresis, Polyacrylamide Gel; D005512:Food Hypersensitivity / Q000276:immunology*; D005916:Globulins / Q000737:chemistry / Q000276:immunology*; D006801:Humans; D015151:Immunoblotting; D007073:Immunoglobulin E / Q000276:immunology; D007526:Isoelectric Point; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011485:Protein Binding; D030262:Soybean Proteins / Q000737:chemistry / Q000276:immunology*
D000485:Allergens; D005916:Globulins; D030262:Soybean Proteins; D007073:Immunoglobulin E; C011474:glycinin