Wheat germ agglutinin (WGA) is affinity purified lectin that non-enzymatically binds to N-acetyl-D-glucosamine and sialic acid residues of glycoproteins and glycolipids. This lectin protects Triticum vulgaris from insects, yeast and bacteria. WGA consists of two subunits and has a molecular weight of 36,000. It is an acidic protein and has mitogenic activity toward lymphocytes. It agglutinates erythrocytes and most types of malignant cells. WGA, similar to insulin, enhances the rate of glucose oxidation in isolated fat cells. It inhibits C5a receptor interaction and is used for isolation and fractionation of insulin receptors.
Colloidal gold can be used to visualize localization of specific saccharide moieties and examine the distribution of plasma membrane glycoproteins based on the binding pattern of Triticum vulgaris Lectin (WGA). Colloidal gold labeled lectins can be viewed via electron microscopy.