ELECTROPHORETIC ANALYSIS OF SEED STORAGE PROTEINS FROM GYMNOSPERMS

Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), pore gradient gel electrophoresis (PGGE) followed by SDS-PAGE and Western blot analysis were used to characterize the seed storage proteins from seven gymnosperm species from the families Pinaceae (Abies alba, Cedrus atlantica and Picea abies), Cupressaceae (Biota orientalis, Chamaecyparis lawsoniana and Cupressus arizonica), and Taxaceae (Taxus baccata). SDS-PAGE and PGGE X SDS-PAGE indicate the presence of proteins with characteristics similar to the 7S globulins in all the species studied. Antibodies to a 7S globulin subunit from Pinus pinaster cross-reacted with homologous polypeptides from Pinaceae species, but not with corresponding subunits from species belonging to other families. Also detected in each of the studied species, with the exception of A. alba and T. baccata, were proteins potentially homologous with 11S proteins. Of these proteins, only those of C. atlantica may be extracted by saline buffer, while the remainder require a dissociating agent. Antibodies raised against the small subunit from P. pinaster. 11S protein recognized only the corresponding polypeptides from Pinaceae species. Overall, these results help clarify our knowledge of gymnosperm seed storage proteins.