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. Multimers. Give rise to a complex array of processed forms, due to a large number of processing sites and changes in glycosylation. Sudden accumulation in cotyledons of 4-day-old plants, but rapidly disappears about 12-14 days after the onset of germination. Causes an allergic reaction in human. Lup an 1 is the major lupin allergen. Conglutin beta is characterized by a broad microheterogeneity with almost a continuum of polypeptides ranging in molecular mass from 15 to 72 KDa. Blad, the major 20 KDa polypeptide, may be considered as a stable, intermediary product of conglutin beta catabolism. 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.