Allergen Data Collection - Update: Soybean (Glycine max)
Internet Symposium on Food Allergens 2(Suppl.3): 1-35 (2000) [http://www.food-allergens.de]
6.6 Properties of Glycinin

6.6.1 Molecular Biological Properties
 
Glycinin References
Allergen Nomenclature none  
Molecular Mass  320-360 kDa (SEC)
6 subunits: 58-62 kDa
each subunit: acidic polypeptide 31-45 kDa, basic polypetide 18-20 kDa
exception: acidic subunit A5 10 kDa
(1) Brooks & Morr 1985
Isoelectric Point acidic subunits pI 4.8-5.5, basic subunits pI 6.5-8.5 (IEF-PAGE, 2D-PAGE)
estimated values according to (1) and (2)
(1) Staswick et al. 1981
(2) Lei & Reeck 1987
Amino Acid Sequence,cDNA, and mRNA
Glycinin
(subunits)
G1 (5)
( A1, BX)
G2 (1)
(A2, B1A)
G3 (4)
(A2, B1)
G4 (3)
(A4, A5, B3)
G (2, 5)
(A3, B4) 
SWISS-PROT: P04776 P04405 P11828 P02858 P04347
GenBank: M36686 X15122 X15123 X02626 M10962
Amino Acids A1a: 287
BX: 180 
A2: 278
B1a: 180
A: 275
B: 180
A4: 257
A5: 97
B3: 185
A3: 320
B4: 172
mRNA 
precursor
1743 bp 1899 bp 1786 bp
cDNA
precursor
  4617 bp 3573 bp    
 
(1) Staswick et al. 1984a
(2) Fukazawa et al. 1985
(3) Momma et al. 1985
(4) Cho & Nielsen 1989
(5) Nielsen et al. 1989
recombinant Protein
Expression in Escherichia coli:
glycinin (A1aB1b and A2B1a) 57 kDa (1)
glycinin  (A1aB1b) with modified functional and nutritional properties (2)
Expression in Yeast:
site-directed mutagenesis of proglycinin (A1a,B1b) (3)
(1) Fukazawa et al. 1985
(2) Kim et al. 1990
(3) Katsube et al. 1998
3D-Structure
X-ray studies of recombinant proglycinin (1, 2)
(1) Gidamis et al. 1994
(2) Utsumi et al. 1996
Posttranslational Modifications
Disulfide bonds
acidic and basic subunits linked by disulfide bond:
A2 Cys-86 to B1a Cys-7 (1)
Glycosylation:
small glycosylated portion of glycinin (approx. 1%) (2)
glycosylation of site-mutated proglycinin (4)
Phosphorylation:
in vitro phosphorylation of Ser-75 and Ser-117 (3)
(1) Staswick et al. 1984b
(2) Lei & Reeck 1987
(3) Fouques et al. 1998
(4) Katsube et al. 1998
Genetic Variants
at least 5 variants (see Amino Acid Sequence) (1)
(1) Staswick et al. 1981
Biological Function
Seed storage protein (11S fraction)
 

 6.6.2 Allergenic Properties
 
Glycinin References
Frequency of Sensitization
IgE-binding to glycinin in 90% of patients (1, 3)
to 11S-fraction (1, 2),acidic- and basic-subunit (a) (2)
to acidic-subunits (A1a, A1b, A2, A3, and A4) (b) (3)
to acidic-subunit (a) (4)
(a) immunoblot
(b) EAST
(1) see 6.1 Sensitization to Soybean Allergens
(2) Burks et al. 1988
(3) Djurtoft et al. 1991
(4) Müller et al. 1998
B-Cell Epitopes
IgE-binding region on acidic chain from glycinin G1:

aa 192-306 (GluC protease digest) (1)

(a) SDS-PAGE / immunoblot

(1) Zeece et al. 1999
Allergenic Potencies
higher IgE-binding to acidic-subunit A4 than to A1a, A1b, A2, and A3 (EAST) (1)
(1) Djurtoft et al. 1991
Alteration of Allergenicity
heat treatment:
soybeans cooked at 100°C for 2h: IgE-binding to stable acidic-subunit (immunoblot) (1)
(1) Müller et al. 1998

 copyright © 2000 by matthias besler -  ONLINE PUBLISHER
home: www.food-allergens.de