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.Separopore® macrobeads are larger size (160-250 micron) than average agarose beads that facilitate coupling of cells and organelles and enzymes. Affinity-purified Griffonia simplicifolia Lectin (GSL I) was immobilized on 4% agarose macrobeads with proper configuration and stability of the lectin.