Cupine

Cupins are very stable storage and defence proteins. Cupins were named after an evolutionary highly conserved protein conformation "barrel domain" (cupa=the Latin term for barrel), which can be found in all representatives of the Cupin family. Cupins have a common evolutionary origin. Their evolution can be followed from bacteria to eukaryotes, including animals and higher plants.

Cupins are grouped in the Cupin Superfamily. The Cupin superfamily is a large group of proteins comprising several thousand proteins, which as a superfamily comprises a multitude of enzymes as well as non-enzymatic seed storage proteins. Cupins take on a variety of functions.

As heat-stable proteins, members of the cupin superfamily play an important role in various allergies, especially those that are directed against 11 S-globulins (e.g. in legumes) and against 7S-globulins (found in vicilins). These occur as "seed storage" - as storage proteins, and as such often represent a component of normal human nutrition. Among the vicilins are the lectins of legumes.

Most plant allergens are derived from the storage organs (hence the name seed storage proteins) of plants (nuts, seeds, legume beans, tubers), or they are used for reproduction. These survival, storage and reproductive structures must be protected by the plants in the best possible way to ensure the survival of the next generation. This explains their resistance to heat (survival in fires) and acids (survival in attacks by acids in the digestive tract of animals).

On the other hand, the storage proteins are highly attractive as food sources for animals, bacteria and fungi. Therefore, there is an evolutionary competition between plants on the one hand to prevent loss and their predators on the other hand.