Phaseolus limensis agglutinin (LBA) is isolated from lima bean seeds and purified by affinity chromatography. LBA is composed of 30,000 Da subunits, of which two are joined by a disulfide bond. Each subunit contains a cysteine residue which is required for both itâ€™s carbohydrate- and metal-ion-binding activities. It has a carbohydrate specificity of terminal GalNAcÎ±(1,3)Gal that elutes with N-acetylgalactosamine. LBA agglutinates blood group A erythrocytes.Cy5, when bound to Phaseolus limensis Lectin (LBA), 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.