Isolated from tomatoes, affinity-purified Lycopersicon esculentum lectin (LEL/LEA) has a carbohydrate specificity toward GlcNac. Composed of a single stable subunit, LEL is a useful marker of tracking vasculature in rodents and in neuroscience research. This lectin has an unusually high carbohydrate content of about 50 percent arabinose and galactose. LEL is non-specific agglutinates human erythrocytes A, B, O, or AB blood types. Protease-treated erythrocytes are slightly more sensitive to agglutination by this lectin.
Cy5, when bound to Lycopersicon esculentum Lectin (LEL/LEA), 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.