Interactions between lectins and other components of leguminous protein bodies

Previous work from this laboratory had shown that Leguminosa seed extracts contain lectin-bound proteins. In the present paper, the isolation of protein bodies from the seeds of 7 Leguminosa species (Canavalia ensiformis, Lens culinaris, Pisum sativum, Glycine max, Sophora japonica, Wisteria floribunda and Phaseolus vulgaris) is described. Protein bodies were characterized microscopically and by their constituents, storage proteins, lectins and some glycosidases. From the protein bodies, lectin-bound proteins were isolated and were shown to be identical with those from whole seed extracts. This indicates a common localization of lectin-bound proteins and of lectins. Lectin-bound proteins belong to the storage proteins and to the proteins with glycosidase activity. The common localization of these proteins and interactions between them suggest a biological role of seed lectins: during maturation they may act as a packaging aid for storage proteins and enzymes into developing protein bodies. Lectins thus may contribute to an ordered construction and degradation of protein bodies.