Isolation of isolectins from Vitis vinifera L-Cv. Chardonnay grape berries

A lectin fraction from Chardonnay grape juice has been isolated by affinity chromatography on a column of p-aminophenyl beta-D-glucoside-derivatized a garose. The lectin fractions agglutinate rabbit and human erythrocytes with out serological specificity. None of the usual monosaccharides, glycosides, or glycoproteins inhibit the hemagglutinating activity. Erythroagglutinati on is only inhibited by nitrophenyl glycosides, p-nitrophenyl beta-D-glucos ide being the strongest inhibitor. In SDS-PAGE in the presence of 2-mercapt oethanol and gel filtration HPLC, the lectin fraction gave a single band or peak corresponding to M-r 13.2-11.9 kDa, thus indicating it to be a monome r. Three bands were observed by isoelectric focusing with pi values of 4.1, 4.4, and 4.9. The isolectins seem to be glycoproteins since they are bound on a concanavalin A-Sepharose column.