Lectins are carbohydrate-binding proteins with specific affinities for distinct sugar moieties, enabling them to selectively bind to carbohydrate groups present on glycoproteins and glycolipids. This specificity varies across different types of lectins; for instance, Wheat Germ Agglutinin (WGA) binds to N-acetyl glucosamine and sialic acid residues, while Concanavalin A (ConA) shows specificity for a-mannosyl and a-glucosyl residues. Peanut Agglutinin (PNA) preferentially binds to Galβ1, and Ulex Europaeus Agglutinin (UEA) binds to a-linked fucose residues. The binding of these lectins can be selectively inhibited by introducing a high concentration of the specific sugar, which competes for binding sites, providing control over lectin interactions.
Unconjugated lectins can be conjugated to beads for the purification of glycoproteins. The conjugated lectins are intended for detection of glycoproteins in histochemical and immunofluorescence experiments.