Use of a single method in the extraction of the seed storage globulins from several legume species. Application to analyse structural comparisons within the major classes of globulins.

In this study, a single, improved methodology was used to extract, fractionate and purify the 11S (legumin-type or related to the alpha-conglutin from Lupinus albus L.), 7S (vicilin-type or related to the beta-conglutin from L. albus) and 2S (related to the gamma-conglutin from L. albus) families of proteins from eight legume species: L. albus, Glycine max (L.) Merr., Pisum sativum L., Vicia faba L., Cicer arietinum L., Phaseolus vulgaris L., Lens culinaris Med. and Arachis hypogaea L. The sedimentation coefficients obtained varied from 1.9 to 8.1 for the gamma-conglutin-related proteins, from 5.1 to 10.5 for the beta-conglutin-related proteins and from 12.0 to 14.9 for the alpha-conglutin-related globulins. The gamma-conglutin-related proteins is the most heterogeneous group. Antibodies produced against each type of gamma-conglutin polypeptide chain recognize the other polypeptide chain as well as other polypeptides in the corresponding globulins from all species examined. The 7S globulins are typically composed of a large number of polypeptides, covering a wide range of molecular masses (10 to 70 kD). The presence of disulphide bonds is apparently absent and the occurrence of glycopolypeptides is not widespread. Finally, the 11S globulins are characteristically formed by a limited number of polypeptides that may be divided into a lighter group (20-25 kD) and a heavier group (35-50 kD). The presence of disulphide bonds is apparently widespread but the occurrence of glycopolypeptides seems to be relatively rare. Both the 7S family and the 11S globulins studied by immunoblotting exhibit a low level of structural similarity.