Strategies in making cross-linked enzyme crystals

Cross-linked enzyme crystal (CLEC) technology provides a unique approach to ameliorating the disadvantages of immobilization. Cross-linking of enzymes results in both stabilization and immobilization of the enzyme without dilution of activity. CLECs are prepared stepwise, with the first step being controlled precipitation of enzymes into microcrystals. The second step is cross-linking with bifunctional agents to form strong covalent intra- and intermolecular bonds between the ε-amino group of lysine residues or by cross-linking between carbohydrate moieties of the enzymes. Inexpensive chemical cross-linking locks the enzyme in the crystalline form, thus enhancing both thermal and proteolytic stability as well as insolubility in both aqueous and organic solvents..