Allium sativum lectin (ASA) is purified first with affinity chromatography and then with gel filtration. It is a dimer of two subunits. ASA binds to a number of α1-2-linked mannose residues. The lectin recognizes internal mannose and binds to the core pentasaccharide of N-linked glycans. In addition, the removal of sialic acids enhances binding activity.
Cy5, when bound to Allium sativum Lectin (ASA), 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.