A soybean lectin having 4-O-methyl-D-glucuronic acid specificity.

Evidence is presented for the presence of a new lectin activity in soybean seeds [Glycine max (L.) Merrill] that has specificity towards the 4-O-methyl-D-glucurono-L-rhamnan exopolysaccharide produced by certain strains of Rhizobium japonicum. Bacterial agglutination and precipitin reactions revealed the lectin activity in phosphate-buffered saline extracts of seeds of all cultivars tested, including the "lectinless" varieties. Reaction of such extracts with carbohydrate haptens demonstrated that the specificity of the binding was towards 4-O-methyl-D-glucuronic acid, D-glucuronic acid and their methyl glycosides.