Seed storage protein. Accumulates during seed development and is hydrolyzed after germination to provide a carbon and nitrogen source for the developing seedling. The alpha-, alpha'-, and beta-subunits associate in various combinations to form trimeric proteins. Localizes in protein storage vacuoles in cotyledons of developing and mature beans (PubMed:17181539, PubMed:15447650, PubMed:12787246, PubMed:16900322). Synthesized and assembled into trimers in the endoplasmic reticulum, and transported to the protein storage vacuoles by the dense vesicles (PubMed:15447650). Causes an allergic reaction in human (PubMed:18996574). Binds to IgE of patients with severe allergic reactions (anaphylaxis) to soybean (PubMed:18996574). Causes an allergic reaction in rat (PubMed:17823539). Induces IgE-mediated passive cutaneous anaphylactic reactions coupled to mast cell degranulation and histamine release after intragastric absorption (PubMed:17823539). A tridecapeptide (MITLAIPVNKPGR), called soymetide and derived from a trypsin digest of CG-1, stimulates phagocytosis of human neutrophils (PubMed:12681509). The N-terminal methionine residue is essential for its activity, and the N-terminal soymetide-4 (MITL) is the minimal structure required for phagocytosis stimulation (PubMed:12681509). Although not formylated at their N-termini, soymetides have a weak affinity for the N-formyl-methionyl-leucyl-phenylalanine (fMLP) receptor (PubMed:12681509). Belongs to the 7S seed storage protein family. Sequencing errors.