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.
Alkaline phosphatase (AP) is conjugated to Cicer arietinum Lectin (CAL/CPA) to show the binding of CAL/CPA in many applications including Western blotting and ELISA. Alkaline phosphatase is a large protein (140 kDa) that catalyzes the hydrolysis of phosphate groups from a substrate resulting in a colored or fluorescent product. The optimal enzymatic activity of this protein is between pH 8 and 10, and its reaction rate remains linear, improving sensitivity over time.