Research on Orientedly Immobilized Urease via Concanavalin A

Abstract In this study, urease was immobilized on chitosan beads via a saccharide-concanavalin A binding. Concanavalin A (ConA) was immobilized on a pre-activated chitosan microsphere, and then oriented immobilization of urease was carried out based on the strong interaction between ConA and glycoprotein. The optimum immobilization conditions were as follows: glutaraldehyde concentration 3.5%, ConA concentration 1 mg/mL, ConA pH 7.0, and urease concentration 0.4 mg/mL. For orientedly immobilized urease, the highest activity was allowed at pH 5.0–6.0 and temperature 77°C, and the Michaelis constant ( K m) was disclosed to be 11.76 mmol/L by Lineweaver-Burk plot. Compared with the free urease and the randomly immobilized urease, the optimum pH of the orientedly immobilized urease was smaller and the pH domain wider. Orientedly immobilized urease presents higher temperature resistance, higher affinity to the substrate, and higher stability of operation. Hence, oriented immobilization of urease via ConA can be a versatile tool for immobilization of proteins and offers great promise in clinical as well as industrial use.