Hordein is a

prolamin Prolamins are a group of plant storage proteins having a high proline amino acid content. They are found in plants, mainly in the seeds of cereal grains such as wheat (gliadin), barley (hordein), rye (secalin), corn (zein), sorghum (kafirin), and ...

glycoprotein Glycoproteins are proteins which contain oligosaccharide chains covalently attached to amino acid side-chains. The carbohydrate is attached to the protein in a cotranslational or posttranslational modification. This process is known as glycos ...

, present in

barley Barley (''Hordeum vulgare''), a member of the grass family, is a major cereal grain grown in temperate climates globally. It was one of the first cultivated grains, particularly in Eurasia as early as 10,000 years ago. Globally 70% of barley pr ...

and some other

cereal A cereal is any Poaceae, grass cultivated for the edible components of its grain (botanically, a type of fruit called a caryopsis), composed of the endosperm, Cereal germ, germ, and bran. Cereal Grain, grain crops are grown in greater quantit ...

s, together with

gliadin Gliadin (a type of prolamin) is a class of proteins present in wheat and several other cereals within the grass genus ''Triticum''. Gliadins, which are a component of gluten, are essential for giving bread the ability to rise properly during baki ...

and other glycoproteins (such as glutelins) coming under the general name of

gluten Gluten is a structural protein naturally found in certain cereal grains. Although "gluten" often only refers to wheat proteins, in medical literature it refers to the combination of prolamin and glutelin proteins naturally occurring in all grain ...

. Horedeins are found in the endosperm where one of their functions is to act as a storage unit. In comparison to other proteins, horedeins are less soluble when compared to proteins such as albumin and globulins. In relation to amino acids, horedeins have a substantial amount of proline and glutamine but lack charged amino acids such as lysine. Some people are sensitive to hordein due to disorders such as

celiac disease Coeliac disease (British English) or celiac disease (American English) is a long-term autoimmune disorder, primarily affecting the small intestine, where individuals develop intolerance to gluten, present in foods such as wheat, rye and barl ...

or gluten intolerance. Along with gliadin (the prolamin gluten found in wheat), hordein is present in many foods and also may be found in beer. Hordein is usually the main problem for coeliacs wishing to drink beer. Coeliacs are able to find specialist breads that are low in hordein, gliadin and other problematic glycoproteins, just as they can find

gluten free beer Gluten-free beer is beer made from ingredients that do not contain gluten such as millet, rice, sorghum, buckwheat or corn (maize). People who have gluten intolerance (including celiac disease and dermatitis herpetiformis sufferers) have a reaction ...

which either uses ingredients that do not contain gluten, or otherwise has the amounts of gliadin or hordein present controlled to stated limits.

References

Gluten Seed storage proteins Glycoproteins {{biochem-stub de:Gliadin