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.
Cy5, when bound to Triticum vulgaris Lectin (WGA), can show the binding pattern of this lectin in cellular imaging and flow cytometry. The excitation wavelength required for Cy5 to fluoresce is high enough to avoid overlap with most other fluorochromes, making it useful for dual-labeling experiments. Because of this high excitation, there is typically less background from autofluorescence of biological specimens.