Vicilins

Vicilins are a class of seed storage proteins belonging to the 7S globulin family in the cupin superfamily. They are among the principal reserve proteins stored in the cotyledons of many legume seeds and provide a source of nitrogen and amino acids during germination. Vicilins are typically synthesized as precursor polypeptides in the endoplasmic reticulum and deposited in protein bodies as mature, soluble globulins. The mature subunits are around 50 to 70 kilodaltons and assemble into higher-order oligomers, often trimers or hexameric complexes, with the 7S globulin fold characteristic of the cupin superfamily.

Taxonomically, vicilins are most abundant in legumes such as soybean, pea, chickpea, lentil, and peanut, but related 7S globulins occur in other angiosperm seeds as well. Many legumes possess multigene families encoding several vicilin polypeptides, which can be processed into distinct subunits (for example, α, α’, and β forms in soy conglycinin).

Functionally, vicilins store amino acids for seedling growth and are studied as a protein source in human and animal nutrition. They are also notable as allergens in some legumes; peanut vicilins, including Ara h 1, are among major peanut allergens, and related vicilins can trigger sensitization in other legume exposures. Because of their abundance and allergenic potential, vicilins are frequently evaluated in food science and plant biology.