Allergens and its types present in soybean

1. Allergens
in
Soybean
Sushant Gawali

2. • Food allergies occur when the body's immune system reacts to certain
proteins in food.
• Soybean allergenic proteins belong to the cupin super-family, they can cause
allergic reactions in human and animals.
• At least 16 different proteins have been discovered in soybean. Soybean
contains various anti-nutritional factors (ANFs), the ingestion of which causes
adverse allergenic symptoms.
• Soybean is listed as one of the “big eight” allergenic foods in the United States
of America, it is also listed as one of the “big twelve” allergenic foods in
Europe.

3. Soybean allergies can be divided into class 1 food allergies and class 2 food allergies
based on differences in sensitization routes.
1. 7S globulin (Gly m 5), 11S globulin (Gly m 6), Gly m 7, Gly m Bd 30K,
Kunitz-type trypsin inhibitor, oleosin, etc. have been identified as class 1 food
allergens causing class 1 allergy.
2. Gly m 3 (profilin) and Gly m 4 (starvation-associated message 2 - SAM22) from
soybeans have been reported as class 2 allergens causing class 2 allergy [i.e.,
pollen–food allergy syndrome (PFAS)]. Both Gly m 3 and Gly m 4 are homologues
of Bet v 2 and Bet v 1, which are birch pollen allergens that mainly cause oral
allergy syndromes (OASs).

4. • At least 16 different proteins have been discovered in soybean. Storage protein β-
conglycinin (7S) and the storage protein glycinin (11S) are the two primary proteins in
soybean.
• They have been recognized as a source of dietary allergens for humans. Studies have
shown that the allergenicity of soybean is mainly due to β-conglycinin, glycinin, Gly m Bd
30 K (P34), and Gly m Bd 28 K.
• Typical symptoms of soy allergy include nausea, vomiting, diarrhea, runny nose, cough,
wheezing, weakness, gastrointestinal distress, dyspnea, cardiovascular or cutaneous
symptoms, and other vague symptoms, up to and including anaphylactic shock, which can
be life-threatening.

5. Proposed mechanism of anaphylaxis derived from soybean allergens

6. Glycinin
Soybean glycinin (Gly m 6) is a component of 11S and the primary storage
protein for soybean seeds, accounting for 19.5%–23.1% of soy protein content and 40%
of total globulin protein content. Glycinin can range in size from 320 to 360 kDa. It
consists of basic chain peptides (BI, BII, BIII, BIV, BV, BVI) and acidic chain peptides (AI,
AII, AIII, AIV, AV) linked by disulfide bonds without undergoing a glycosylation reaction.
Acidic glycinin chain is the primary source of allergic reactions in hypersensitive patients
and the basic glycinin chain can also bind to IgE and elicit an allergy response.
Gly m Bd 60K (α-subunit of β-conglycinin)
The other allergenic protein in the 7S-globulin fraction, which was recognized by
about 25% of sera from soybean-sensitive patients with atopic dermatitis, was identified
as an α-subunit of β-conglycinin. The IgE antibodies recognizing the α subunit showed no
cross reactivity against either α’ or β subunit of β-conglycinin known to be highly
homologous to a subunit.

7. Gly m Bd 30 K
One of the most allergenic storage proteins of soybean, is frequently identified
by IgE in the serum of people with soybean allergies and can cause atopic dermatitis.
The molecular weight is approximately 43 kDa, and it contains 379 amino acids.
Gly m Bd 28 K
Gly m Bd 28 K is another 7S soybean moiety that has been reported as an
essential allergen of the asparagine glycoprotein and consists of 220 amino acid residues
present in the oligomeric type. It is a low abundance protein (26 kDa) belonging to the
cupin superfamily with a β-barrel structure.

8. Soybean allergen detection methods:
1. Immunoanalytical methods
a. Enzyme-linked immunosorbent assay (ELISA)
• Competitive ELISA (cELISA)
• Sandwich ELISA (sELISA)
• Indirect ELISA (iELISA)
b. Enzyme-allergosorbent test (EAST) and radio-allergosorbent test (RAST)
c. Lateral flow immunoassay (LFIA)
d. Immunoblotting/Western blot
2. Mass spectrometry (MS)
3. Polymerase chain reaction (PCR)
4. Biosensors

9. R E F E R E N C E S
• Detection and inactivation of allergens in soybeans: A brief review of recent research
advances. Lina Tokuna Mulalapele and Jun Xi., Grain & Oil Science and Technology (2021) 4:91–200.
• Comparison of Various Soybean Allergen Levels in Genetically and Non-Genetically
Modified Soybeans. Ayato Matsuo, Kaho Matsushita, Ayano Fukuzumi, Naoki Tokumasu, Erika
Yano, Nobuhiro Zaima, and Tatsuya Moriyama, Foods 2020.
• Soybean Allergens and Hypoallergenic Soybean Products. Tadashi Ogawa, Masahiko Samoto
And Koji Takahashi., J. Nutr. Sci. Vitaminol (2000) 46:271-279.
• Quantitation of Soybean Allergens Using Tandem Mass Spectrometry. Norma L. Houston et
al., Journal of Proteome Research (2011) 10:763-773.
• Advances of Research on Glycinin and β-conglycinin: a Review of two Major Soybean
Allergenic Proteins. Tao Wang, Gui-xin Qin, Ze-wei Sun & Yuan Zhao, Critical Reviews in Food
Science and Nutrition 2013.

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