Bauhinia purpurea agglutinin or lectin (BPA/BPL) is a tetrameric lectin with a molecular weight of 195,000. Binding appears to be highest for glycoconjugates containing galactosyl (β-1,3)N-acetylgalactosamine structures but oligosaccharides with a terminal α-linked N-acetylgalactosamine can also bind. BPA is lactose-specific and elutes with the sugar lactose. It has specificity for blood groups A, B, O (-SA). Treatment of erythrocytes with neuraminidase or trypsin will increase the agglutination reaction, indicating that the receptor is masked by terminal carbohydrates.
Although binding specificity is similar to that of peanut agglutinin, tissue staining patterns of these two lectins are distinct. Makela's group 2 sugars, particularly N-acetyl-D-galactosamine, are potent inhibitors. The native protein appears to be stable in detergent solution.
Biotin is a small molecule involved in a wide range of metabolic processes. This ligand forms a complex with Avidin and Streptavidin, resulting in the strongest non-covalent protein-ligand interaction known. Biotinylated Bauhinia purpurea Lectin (BPL/BPA) has an appropriate amount of biotin bound to provide optimum detection characteristics when using an Avidin-HRP or Streptavidin-HRP conjugate. Biotinylated lectins allow for more sensitive detection in ELISA and Western-blotting applications.