Datura stramonium agglutinin or lectin (DSA/DSL) is purified by affinity chromatography. Seeds of Datura stramonium contain at least three different carbohydrate-binding proteins, and the most prominent lectin is a dimeric glycoprotein composed of two nonidentical subunits that contains 40% carbohydrate. It binds well to N-acetylglucosamine, oligomers, and branched pentasaccharide, including two N-acetylglucosamine disaccharides linked to mannose (Î²-1,6) and (Î²-1,2), which is known to be the most potent inhibitor of agglutination. DSL prefers binding to (GlcNAc)2-4 and elutes with the sugar chitin hydrolysate. DSL binds well in the acidic pH range and its affinity decreases above pH 8.0. This agglutinin has blood group A, B, and O specificity. Studies have shown that DSA can act as a biomarker for neoplastic urotherial cells.Cy5, when bound to Datura stramonium Lectin (DSA/DSL), 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.