The proteins from Vicia sativa L. (common vetch) seeds were investigated. Protein comprises approximately 11.4% of the seed fresh weight, >50.8% of which is composed by globulins and 43.6% by albumins. The globulins may be fractionated into two main components, which were named alpha-vicinin (comprising 73% of the total globulin fraction, and hence >37% of the total seed protein) and beta-vicinin. Two minor globulin components are also present, gamma-vicinin and delta-vicinin. alpha-Vicinin, the legumin-like globulin, with a sedimentation coefficient of 10.6 S, is a nonglycosylated, disulfide-bond-containing globulin, composed of a group of subunits with molecular masses ranging from 50 to 78 kDa. Upon reduction, each of these subunits releases a heavy polypeptide chain (34-66 kDa) and a light polypeptide chain (21-23 kDa). beta-Vicinin, the vicilin-like globulin, with a sedimentation coefficient of 7.7 S, is a nonglycosylated globulin that contains no disulfide bonds and consists of two major polypeptides with molecular masses of 58 and 66 kDa. gamma-Vicinin is a minor, glycosylated, disulfide-bond-containing globulin. In the reduced form, it comprises six polypeptide chains with molecular masses of 12, 19, 21, 22, 23, and 31 kDa. Finally, delta-vicinin is a minor, highly glycosylated globulin that exhibits hemagglutinating activity. It is composed of a major 47 kDa polypeptide and two minor (33 and 38 kDa) polypeptides. N-terminal sequencing of the delta-vicinin 47 kDa polypeptide revealed no homology to any other known storage protein.