Griffonia simplicifolia lectin (GSL I) is affinity purified from a woody climbing shrub native to Africa. GSL I is composed of two types of subunits A and B that combine to form tetrameric structures, resulting in five isolectins. This lectin has affinity for terminal Î±-D-galactosyl residues and terminal N-acetyl-Î±-D-galactosaminyl residues. The A-rich lectin preferentially agglutinates blood group A erythrocytes and thus appears to be specific for Î±-N-acetylgalactosamine residues, while the B-rich lectin preferentially agglutinates blood group B cells and is specific for Î±-galactose residues. This lectin shows specificity for blood group B greater than blood group A1.GSL I has been reported to bind several glycoproteins including laminin. Since some Î±-D-galactosyl residues are expressed in endothelial cells of mouse tissues, GSL I can present a highly specific surface of glycosylation pattern in these cells.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 Griffonia simplicifolia Lectin (GSL I) 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.