Affinity chromatography of glucose‐specific lectin using silica‐based support

Four silica‐based adsorbents were prepared from covalent attachment of four carbohydrates: i. e. maltose, cellobiose, N‐acetyl‐D‐glucosamine and p‐aminophenyl‐β‐D‐glucopyranoside, respectively. These adsorbents posses either terminal D‐glucose or N‐acetyl‐D‐glucosamine as the ligand on their surfaces with a ligand density ranging from 20 to 29·2 μmol g−1. The binding of the glucose‐specific lectin, concanavalin A (Con A), to the immobilized ligand on the silica surface depended on the configuration of the immobilized glucose and the linkage of the glucose to the support. Con A showed strong affinity for maltose‐immobilized silica, which contains terminal α‐D‐glucose, and p‐aminophenyl‐β‐D‐glucopyranoside‐immobilized silica. On the other hand, Con A showed no affinity for cellobiose‐immobilized silica, which contains terminal β‐D‐glucose groups, and N‐acetyl‐D‐glucosamine‐immobilized silica. The binding constants for the interactions between Con A and immobilized ligands were determined. The columns packed with the resultant affinity adsorbents were then adopted for the purification of Con A from Jack bean meal. As the diluted NaCl extract of Jack bean meal was applied to the column packed with maltose‐immobilized silica, a 13·2‐fold purification was achieved by stepwise‐elution.