Cholinesterase based amperometric biosensors for assay of anticholinergic compounds

Cholinesterases and Engineered Mutants for the Detection of Organophosphorus Pesticide Residues

Nowadays, pesticide residues constitute an increasing public health concern. Cholinesterases, acetylcholinesterase, and butyrylcholinesterase, are reported to be involved in detoxification processes owing to their capability of scavenging organophosphates and carbamates. Thus, these enzymes are targeted for the discovery of sensors aiming at detecting pesticide residues. In recent years, cholinesterase-based biosensors have attracted more and more attention in the detection of pesticides. Herein, this review describes the recent progress on the engineering of cholinesterases and the development of the corresponding sensors that could be used for the detection of organophosphorus pesticide residues.

Design, synthesis, biological evaluation, and molecular modeling of coumarin-piperazine derivatives as acetylcholinesterase inhibitors

Acetylcholinesterase (AChE) is an important drug target for the treatment of Alzheimer's disease. A novel series of coumarin-piperazine derivatives were synthesized and their potency to inhibit human AChE enzyme (hAChE) was studied. All the final compounds were characterized by infrared, (1)H NMR, (13)C NMR, and elemental analysis. Docking experiments of the designed coumarin-piperazine derivatives were carried out in order to compare the theoretical and experimental binding affinities toward hAChE, to delineate the inhibitory mechanism. Subsequently, a structure-activity relationship (SAR) study using the molecular field method showed that the hydrophobic field and positive charge center conferred by the coumarin and piperazine moieties demonstrated an inhibitory mechanism. Among the compounds tested, 3f, 3j, and 3m were found to be the most potent inhibitors of hAChE.

Biosensors based on enzyme inhibition

The present chapter describes the use of biosensors based on enzyme inhibition as analytical tools. The parameters that affect biosensor sensitivity, such as the amount of immobilized enzyme, incubation time, and immobilization type, were critically evaluated, highlighting how the knowledge of enzymatic kinetics can help researchers optimize the biosensor in an easy and fast manner. The applications of these biosensors demonstrating their wide application have been reported. The objective of this survey is to give a critical description of biosensors based on enzyme inhibition, of their assembly, and their application in the environmental, food, and pharmaceutical fields.

Electrogravimetric real-time and in situ michaelis-menten enzymatic kinetics: progress curve of acetylcholinesterase hydrolysis

A piezoelectric detection of enzyme-modified surface was performed under Michaelis-Menten presumptions of steady-state condition. The approach herein presented showed promise in the study of enzymatic kinetics by measuring the frequency changes associated with mass changes at the piezoelectric crystal surface. Likewise, real-time frequency shifts, that is, dΔf/dt, indicated the rate of products formation from enzymatic reaction. In this paper, acetylcholinesterase was used as the enzymatic model and acetylcholine as substrate. The enzymatic rate has its maximum value for a short time during the kinetic reaction, for instance, during the first ten minutes of the reaction time scale. The values found for the kinetic constant rate and Michaelis-Menten constant were (1.4 ± 0.8) 10(5) s(-1) and (5.2 ± 3) 10(-4) M, respectively, in agreement with the values found in classical Michaelis-Menten kinetic experiments.