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, fraction ate and purify the 11S (legumin-type or related to the alpha -conglutin fro m Lupinus albus L.), 7S (vicilin-type or related to the beta -conglutin fro m 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., P isum 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-relat ed proteins is the most heterogenous group. Antibodies produced against eac h type of gamma -conglutin polypeptide chain recognize the other polypeptid e chain as well as other polypeptides in the corresponding globulins from a ll species examined. The 7S globulins are typically composed of a large num ber 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 cha racteristically formed by a limited number of polypeptides that may be divi ded into a lighter group (20-25 kD) and a heavier group (35-50 kD). The pre sence of disulphide bonds is apparently widespread but the occurrence of gl ycopolypeptides seems to be relatively rare. Both the 7S family and the 11S globulins studied by immunoblotting exhibit a low level of structural simi larity.