Seed storage protein. Accumulates during seed development and is hydrolyzed after germination to provide a carbon and nitrogen source for the developing seedling. Component of globulins complexes which accumulate in seeds. Increased expression during seed filling, with a maximum between 33 and 38 days after anthesis. Causes an allergic reaction in human. Lup an 1 is the major lupin allergen. The variability of the residues taking part of IgE-binding epitopes might be responsible of the difference in cross-reactivity among legumes. Belongs to the 7S seed storage protein family.