Seed storage protein. Accumulates during seed development and is hydrolyzed after germination to provide a carbon and nitrogen source for the developing seedling. Has a lectin-like activity. Causes an allergic reaction in human. Lup an 1 is the major lupin allergen. The initial characterization of blad (PubMed:9299789) was made on a seed storage protein extract containing both conglutin beta 1 and 2. Belongs to the 7S seed storage protein family.