High Stability of Immobilized Acetylcholinesterase on Chitosan Beads

• Published in: ChemistrySelect (Weinheim) Vol. 5; no. 15; pp. 4623 - 4627
• Main Author: Işık, Mesut
• Format: Journal Article
• Language: English
• Published: 23-04-2020
• Subjects: Acetylcholinesterase; Chitosan-glutaraldehyde; Immobilization; Inhibitors; Storage stability
• ISSN: 2365-6549; 2365-6549
• DOI: 10.1002/slct.202000559

The enzymes are unstable and have a short lifetime; this causes a decrease in the number of enzyme usage and increases the cost. In the study, the acetylcholinesterase (AChE) enzyme was covalently immobilized to the surface of chitosan via glutaraldehyde by cross‐linking method, where glutaraldehyde contains functional amine group. The immobilized enzyme was characterized by scanning electron microscopy‐energy dispersive X‐ray analysis (SEM‐EDX). The operational and storage stability of immobilized AChE was found higher than the free enzyme by the spectrophotometric method. The storage stability of the immobilized AChE was found 81% for 60 days, while the free AChE lost a high ratio of its activity in 30 days. It was observed that 93% activity was preserved for the immobilized enzyme after reusing it approximately 30 times. Moreover, kinetic parameters, the Km and Vmax, were found 0.073 mM and 0.244 EU/mL for immobilized AChE and 0.044 mM and 0.362 EU/mL for free AChE, respectively. The AChE enzyme is used in the analysis of pesticides; that is why the high stability and reusability of the enzyme as a result of immobilization proses are important in biotechnological applications.
The acetylcholinesterase (AChE) enzyme was immobilized on chitosan surface by crosslinking via glutaraldehyde. The presence of the immobilized enzyme on the chitosan surface was confirmed by scanning electron microscopy‐energy dispersive X‐ray analysis (SEM‐EDX). The kinetic properties, storage and operational stability of AChE were determined before and after the immobilization on chitosan surface. The stability of the AChE enzyme has been observed to increase with immobilization.