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 Î±1-2-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. 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 Allium sativum Lectin (ASA). Colloidal gold labeled lectins can be viewed via electron microscopy.