THE UNUSUAL EXTRACELLULAR LOCALIZATION OF CONGLUTIN-GAMMA IN GERMINATING LUPINUS-ALBUS SEEDS RULES OUT ITS ROLE AS A STORAGE PROTEIN

Antibodies specific to conglutin gamma, a putative storage glycoprotein of Lupinus albus seeds, and to one of its constituent subunits devoid of carbohydrate, have been used to localize the protein in mature and germinating seeds by light and electron microscopy. Conglutin gamma is located within the protein bodies of mature seeds, but after 2 days of germination labelling is also observed in the extracellular spaces of the cotyledonary tissue. By 8 days after germination, when most of the protein bodies and their electron dense contents have disappeared, conglutin gamma is found predominantly within the intercellular spaces. In parallel experiments labelling of a typical lupin storage protein, a legumin-like globulin, was shown to be confined to the protein bodies in both mature and germinating seeds, but not to be localized within the intercellular spaces. On the basis of these findings the role of conglutin gamma as a storage protein is questioned.