High Stability of Immobilized Acetylcholinesterase on Chitosan Beads

Abstract

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.[a] Dr. M. Işık

Synthesis, characterization, biological evaluation, and in silico studies of novel 1,3‐diaryltriazene‐substituted sulfathiazole derivatives

“…[49,50] Additionally, the AChE (EC 3.1.1.7) inhibitory effects of the novel 1,3diaryltriazene-substituted sulfathiazole compounds (ST1-11) were determined according to the procedure of Ellman et al [51] They were recorded spectrophotometrically at 412 nm using acetylthiocholine iodide as the substrate for the enzymatic reaction, as in previous studies. [52][53][54][55] In addition, the inhibitory effect of novel compounds (ST1-11) on α-GLY (EC 3.2.1.20) activity was determined using the p-nitrophenyl-D-glycopyranoside (p-NPG) substrate according to the analysis of Tao et al [56] and according to previous works. [57,58] The inhibition effects of the derivatives (ST1-11) on these enzymes were determined by Activity%-Analog curves.…”

Synthesis, Characterization, and Inhibition Study of Novel Substituted Phenylureido Sulfaguanidine Derivatives as α‐Glycosidase and Cholinesterase Inhibitors

“…In this case, it was emphasized that diabetes mellitus could be associated with the observed cognitive disorders [18,19] . Studies have proven long ago that one of the important metabolic enzymes responsible for the cholinergic system is the AChE enzyme [20–22] …”

Conducting polymer‐based electrochemical biosensor for the detection of acetylthiocholine and pesticide via acetylcholinesterase

“…Immobilization is an important factor that increases the stability of enzymes. In a study conducted by Işık, the storage and operational stability of AChE, immobilized to the chitosan surface, was reported to be quite high compared to the free enzyme [43]. The immobilized AChE activity was found to be 75% more stable than the free enzyme in a study conducted by Gabrovska et al [44], where AchE was immobilized on acrylonitrile copolymer membranes.…”