Improved procedures for purification of the Bandeiraea simplicifolia I isolectins and Bandeiraea simplicifolia II lectin by affinity chromatography.

Bandeiraea simplicifolia plant seeds contain a family of five alpha-D-galactopyranosyl-binding isolectins (BS I-A4, A3B, A2B2, AB3, B4) and N-acetyl-D-glucosamine-binding lectin (BS II). After Pi/NaCl extraction and ammonium sulfate fractionation BS II is specifically adsorbed onto p-aminobenzyl-1-thio-N-acetyl-beta-D-glucosaminide-succinylaminohexylaminyl--Sepharose-4B. The BS I isolectins pass through this column and BS II is selectively eluted by Pi/NaCl containing 2 mM N-acetyl-D-glucosamine or by 0.1 M sodium acetate buffer pH 3.6. The material not bound to the column is loaded onto p-aminophenyl-beta-D-galactopyranosyl-succinylaminohexylaminyl--Sepharose-4B. BS I-A4 is specifically eluted in a sharp peak with Pi/NaCl containing 1 mM N-acetyl-D-galactosamine. Then, BS I-A3B, A2B2, AB3 and B4 are selectively eluted, in a single peak for each isolectin. with Pi/NaCl containing 2 mM, 8 mM, 15 mM and 50 mM methyl alpha-D-galactopyranoside, respectively.