This is simplified information about 2S seed storage proteins – there are more resources available at the bottom of the page for further reading for those who are interested in knowing more.

What are 2S seed storage proteins?

They are water soluble proteins found in a wide variety of nuts, seeds, fruit and vegetables. As allergenic proteins go, they are very stable, which means they are not easily damaged by extreme changes in temperature or pH due to their small size and compact structure. This means that the proteins ability to trigger and allergic reaction in a sensitised individual would not be hindered by cooking, freezing, digestion or in many cases food processing.

Their function in plants is as a source of nutrients during germination and growth of seedlings. They are also thought to also to play a role in defence against plant pathogens.

2S albumins are a part of the prolamin superfamily; other allergenic proteins included in this superfamily are lipid transfer proteins and prolamin storage proteins of cereals.

What foods are 2S seed storage proteins found in?

In the top 14 foods, peanuts, cashews, brazil nut, mustard, pecan, hazelnut, soya beans, walnut, pistachio, sesame and almonds all contain 2S seed storage proteins.

Fruits and vegetables containing these proteins are kiwi, turnip, pumpkin, lemon, tangerine, yuzu and sichuan pepper.

2S seed storage proteins are also found in rapeseed, buckwheat, flaxseed, castor beans, mung bean, chickpea, sunflower seeds, poppy seeds, cocoa, fenugreek, pink peppercorn, quinoa and pine nuts.

What symptoms can 2S seed storage proteins cause?

Allergy to foods containing 2S seed storage proteins have a wide range of symptoms and severity including urticaria (hives or welts), angioedema (swelling under the skin), nausea, abdominal pain, vomiting or breathlessness and anaphylactic shock.

You can download a Seed Storage Protein Factsheet from the Allergy Resources Ko-fi Shop for just $0.90 (£0.69 or €0.82). This has up to date information on which foods contain linked allergens and what to avoid if you think you are allergic to seed storage proteins.

If you are interested in which foods contain which allergenic proteins you can visit the Food Allergy Tool Page.

Are 2S seed storage proteins different from 7S and 11S seed storage proteins?

Many of the foods containing 2S seed storage proteins will also contain 7S seed storage proteins, also called vicilin and 11S seed storage proteins, also called legumin. 7S and 11S seed storage proteins are globulins and 2S seed storage proteins are albumins. Globulins are storage proteins found most often in legumes and albumins are water soluble proteins found more often in nuts and seeds.

2S refers to the sedimentation co-efficient of the protein (a measure of how quickly the protein sediments in a centrifuge). These three proteins look similar but they have differing chemical compositions.

A Table of Cross Reactivity between 2S, 7S and 11S seed storage proteins

You can download a Seed Storage Proteins Chart from my KOFI page for just 25p!

How Cross Reactive are 2S albumin proteins?

The 2S seed storage proteins in many foods look very similar, but it is not guaranteed that an allergy to one food will result in cross reactivity with another.

There has been shown to be cross reactivity across the Brassicaceae family, including oilseed rape, turnip rape and mustard.

Please visit the Food Index of this site if you are interested in the cross reactivity of a specific food, there are lots of resources dedicated to cross reactivity.

Science Direct – What are Prolamins?

Science Direct – What are Storage Proteins?

Sunflower seed allergy: Identification of novel 2S-albumins as potential marker allergens, 2024

Comprehensive amino acid composition analysis of seed storage proteins of cereals and legumes: identification and understanding of intrinsically disordered and allergenic peptides, 2024

An Overview of Fruit Allergens: Structural, Functional, Phylogenetical, and Clinical Aspects, 2023

Food Allergens of Plant Origin, 2023

Seed Storage Protein, Functional Diversity and Association with Allergy, 2022

Recent Advances in Electrochemical Sensing Strategies for Food Allergen Detection, 2022

2S albumin and 11S globulins, two storage proteins involved in pumpkin seeds allergy, 2020

Purification and characterization of 2S albumin from Nelumbo nucifera, 2016

2S Albumin Storage Proteins: What Makes them Food Allergens? 2008

Let me know if you found any of these interesting or useful. If you spot an article or research that you think is interesting you can message me or tag me on Facebook or Twitter - links at the bottom of the page.