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. Allium sativum Lectin (ASA) is labeled with fluorescein isothiocyanate (FITC) and has an appropriate number of fluorochromes bound to provide the optimum staining characteristics for this lectin. FITC conjugates have been used in a variety of immunohistochemical and flow cytometry applications. Fluorescein conjugates display a high rate of photobleaching, signal is sensitive to pH changes, broad fluorescence emission spectrum, and fluorescence quenching on conjugation to biopolymers.