Cicer arietinum lectin or agglutinin (CAL/CPA) is a homodimer composed of two subunits.This lectin is a glycoprotein that contains 4.5% neutral sugars and is basic in nature (pI: 9.0). It’s haemagglutination activity is inhibited by fetuin and desialylated fetuin with a carbohydrate specificity for fetuin and p-Nitrophenyl N-acetyl-α-D-galactoside. CAL possess complex-sugar specificity for N-glycans and N-acetyl-D-galactosamine, and elutes with acetyl-D-galactosamine. Although neither human or rabbit erythrocytes are agglutinated by this lectin, pronase-treated rabbit and human erythrocytes have been successfully agglutinated. None of the sugars, such as glucose, mannose or galactose, nor their derivatives, disaccharides, trisaccharides and tetrasaccharides have any effect on the agglutination of this lectin.
Cy5, when bound to Cicer arietinum Lectin (CAL/CPA), 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.