Immobilization of β‐galactosidase for application in organic chemistry using a chelating peptide

Abstract

The strong interaction of hexa‐histidine fusion proteins with metal chelate adsorbents was utilized to immobilize β‐galactosidase with a hexa‐histidine peptide at the N‐terminus to the Ni²⁺‐nitrilotriacetic acid adsorbent. The fusion protein was cloned and expressed in Escherichia coli. The purified soluble fusion protein showed the same specific activity as the purified β‐galactosidase and retained 64 percent of its β‐galactosidase activity when bound to the adsorbent. To demonstrate the potential of the immobilized β‐galactosidase in organic chemistry, allyl‐β‐D‐galactosidase was synthesized from lactose and allyl alcohol on a gram scale. The same enzyme preparation was reused in three subsequent batches to prepare the model compound with high yield. © 1993 John Wiley & Sons, Inc.