Lectin from Bandeiraea simplicifolia (Griffonia simplicifolia)

BS-I has a major affinity for terminal α-D-galactosyl residues with a secondary affinity for terminal N-acetyl-α-D-galactosaminyl residues.

Purified by affinity chromatography using the method of Hayes, C. E., and Goldstein, I. J., J. Biol. Chem., 249, 1904 (1974).

Agglutination activity is expressed in μg/mL and is determined from serial dilutions of a 1 mg/mL solution using phosphate buffered saline, pH 6.8, containing, for each lectin, calcium, magnesium, and manganese at different concentrations. This activity is the lowest concentration to agglutinate a 2% suspension of appropriate erythrocytes after 1 hr incubation at 25 °C.

BS-I is a tetrameric lectin consisting of two types of subunits designated A and B. There are five BS-I isolectins with different subunit composition: BSI-B₄, BSI-AB₃, BSI-A₂B₂, BSI-A₃B and BSI-A₄. BSI-B₄ is blood group B specific and has an exclusive affinity for terminal α-D-galactosyl residues, whereas BSI-A₄ has blood group A specificity and has a major affinity for terminal N-acetyl-α-D-galactosaminyl residues.