ISOLATION OF A NOVEL PLANT LECTIN WITH AN UNUSUAL SPECIFICITY FROM CALYSTEGIA-SEPIUM

A novel plant lectin has been isolated from the rhizomes of Calystegia sepium (hedge bindweed) and partially characterized. The lectin is a dimeric protein composed of two identical non-covalently linked subuni ts of 16 kDa. Hapten inhibition studies indicate that the novel lectin is best inhibited by maltose and mannose and hence exhibits a sugar b inding specificity that differs in some respects from that of all prev iously isolated plant lectins. Mitogenicity tests have shown that the Calystegia lectin is a powerful T-cell mitogen. Affinity purification of human, plant and fungal glycoproteins on immobilized C. sepium lect in demonstrates that this novel lectin can be used for the isolation o f glycoconjugates from various sources. Moreover, it can be expected t hat by virtue of its distinct specificity, the new lectin will become an important tool in glycobiology.