Jacalin lectin (AIA) is purified by affinity chromatography and is tetrameric two-chain structure consisting of four identical protomers with an isoelectric point of pH 7.8. The lectin has specificity for blood group types O (+SA) and T. Jacalin is considered a galactose-specific lectin and elutes with galactose or melibiose. A post-translational proteolytic modification of Jacalin gives the lectin a novel carbohydrate-binding site involving the N terminus of the α-chain. The protein’s structure explains it’s carbohydrate-binding specificity of T-antigen disaccharide Galβ1,3GalNAc. Potent inhibitors of jacalin include D-galactose, β-Met-Gal and 2-deoxy-α-D-galactose.
Alkaline phosphatase (AP) is conjugated to Artocarpus integrifolia (Jacalin) Lectin (AIA) to show the binding of AIA 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.