Voltammetric assay of butyrylcholinesterase in plasma samples and its comparison to the standard spectrophotometric test

Pohanka, Miroslav

doi:10.1016/j.talanta.2013.11.045

Cited by 29 publications

(13 citation statements)

References 47 publications

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“…In past, simple spectrophotometric tests based on 5,5 -dithiobis-(2-nitrobenzoic) acid as the chromogenic reagent and acetyl-(or butyryl-)thiocholine as the substrate (Ellman et al, 1961;George & Abernethy, 1983;Gorun et al, 1978), potentiometric tests with pH titration (Bazire et al, 2011), and electrochemical sensors and biosensors (Khaled et al, 2010;Pohanka, 2014) have been employed. The mentioned testes are based on an addition of reagents to the sample followed by measurements of the enzyme activity.…”

Section: Introductionmentioning

confidence: 99%

Determination of acetylcholinesterase and butyrylcholinesterase activity without dilution of biological samples

Pohanka

2015

Chemical Papers

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Two cholinesterases: acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), are known. The enzymes are important in the body and alteration of their activity has significant use in the diagnosis of poisoning, liver function, etc. Currently available methods for the determination of cholinesterases have some major drawbacks including various interferences and the inability to be used for decreasing the enzyme activity in the presence of reversible inhibitors due to sample dilution; hence, a method for dilution free assay of cholinesterases is desired. Here, microplates were modified with indoxylacetate (100 µL of 10 mmol L −1 solution) and used for cholinesterases assay after drying at 37 • C. The fact that indoxylacetate remains stable in dry state and serves simultaneously as a chromogen and substrate provide good prerequisites for the method. The limit of detection for BChE was 0.71 U while that for AChE was 2.8 U per a 100 µL sample (solution of enzyme or plasma sample). The limit of detection is low enough to allow standard examination of cholinesterasemia. The two cholinesterases can be distinguished from each other using selective inhibitors such as donepezil and iso-OMPA. The new method was also successfully validated for the standard Ellman's assay using plasma samples with BChE activity adjusted by carbofuran. The new method based on indoxylacetate seems promising for routine tests.

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Section: Introductionmentioning

confidence: 99%

Determination of acetylcholinesterase and butyrylcholinesterase activity without dilution of biological samples

Pohanka

2015

Chemical Papers

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“…The obtained results (Table ) were in agreement with the previous potentiometric and official methods . In addition, the proposed potentiometric method showed average recoveries comparable with Ellman′s spectrophotometric method for acetylcholinesterase activity with the advantage that simple, inexpensive analysis protocol can be applied in field measurement with portable systems.…”

Section: Resultsmentioning

confidence: 99%

“…Aliquots of the sample solution were diluted to the suitable concentration and analyzed by the proposed enzymatic procedures in comparison to the official European Pharmacopoeia and official spectrophotometric Ellman′s method for acetylcholinesterase activity . Standard spectrophotometer microplate reader was consequently filled with 400 μL of 5,5‐dithiobis‐(2‐nitrobenzoic) acid 10 −3 mol L −1 , 100 μL of AChE solution,100 μl of tested compound or phosphate buffered and 300 μL of phosphate buffered.…”

Section: Methodsmentioning

confidence: 99%

Novel Enzymatic Potentiometric Approaches for Surfactant Analysis

et al. 2016

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1IntroductionSurfactants form au nique class of organic compounds which generally consist of ah ydrophilic head group and ah ydrophobic chain (or tail) [1].T he hydrophobic part is usually hydrocarbon chain (C 8 -C 18 ), while the hydrophilic group may be carboxylates,s ulfates, sulfonates (anionic), polyoxyethylenated chains (nonionic) or quaternary ammoniums alts in case of cationic surfactants [1][2][3].Thew orldwide production of surfactants was about 13 million metric tonsi n2 008;7 0% of them represent anionico nes.S urfactants are mainly employed in formulation of detergents,p ersonal-care products, paints,p esticides and textile industry [4][5][6].A fter application, surfactants are discharged into waste treatment units and then dispersed into the environment causings erious toxic effects on aquatic organismsw hen discharged with massive quantities [7][8][9].Thew idespread applications of surfactants and their environmental impacts were reflected on the development of reliable,r apid and accurate procedures for surfactanta nalysis [10][11][12][13][14][15][16][17].T wo-phaset itrationi st he most populara nalytical method for ionic surfactants in water samples [18]. Thet arget surfactant is extracted into organic solvent via formation of lipophilic ion-pair with suitable titrant in presence of an ionic dye which colors the organic layer differently at the end point. Formation of emulsion during titration,t oxicity of the chlorinated organics olvent and lack of efficiency for short chain surfactanta re the main drawbacks of such method [14].P otentiometric approaches using ion selective electrodes (ISEs) are promising option for analysis of surfactants,offering simple measuring protocol and sample pre-treatment. Surfactant potentiometric sensors are usually used as titration end-point indicator electrodes;a lthough some direct potentiometric surfactant sensors have also been reported [13,17,19,20].Liquid and PVC membranes electrodes [21,22] are inconvenient as they are mechanically complicated with difficulty of miniaturization and short lifetime. Solid-state electrodes were reported referring to an ew type of ISEs in which the internal reference elementw as in direct contact with the electroactive membrane [13,20,[23][24][25]. Elimination of the internal reference solution leads to certain advantageous such as simplicity,m iniaturization and ability to operatea th igher pressuree nvironment where the PVC membrane can be damaged.C arbon paste electrodes (CPEs) were introduced as end-point indicator electrode for potentiometric titration of surfactants [19,20] with very short response time in addition to the ease of fabrication and regeneration. However,d esigns and shapes of the aforementioned sensors were inconvenient for every purpose such as flow injection analysis or portable analyzers where the measuring unitsr equired sensors of special constructions and size.Thep ractical and economic interests have been driven the development of various kindso fd isposal electrochemical sensors based on screen-print...

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“…Measuring of AChE activity is important in diagnostics or serves as a tool in analytical chemistry in inhibitor determination. A commonly acknowledged method for activity determination is Ellman’s reaction but there is potential for pH or electrochemical detection [2,3,4,5,6,7]. There is a demand for the determination of AChE inhibitors in a wide spectrum of used compounds like Alzheimer’s disease drugs (donepezil, rivastigmine, huperzine, galantamine), pesticides (carbofuran, malaoxon, malathion), and chemical warfare agents (sarin, soman, tabun, VX) [8].…”

Section: Introductionmentioning

confidence: 99%

Construction of an Acetylcholinesterase Sensor Based on Synthesized Paramagnetic Nanoparticles, a Simple Tool for Neurotoxic Compounds Assay

Kostelník

Kopel

Cegan

et al. 2017

Sensors

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Magnetic particles (MPs) have been widely used in biological applications in recent years as a carrier for various molecules. Their big advantage is in repeated use of immobilized molecules including enzymes. Acetylcholinesterase (AChE) is an enzyme playing crucial role in neurotransmission and the enzyme is targeted by various molecules like Alzheimer’s drugs, pesticides and warfare agents. In this work, an electrochemical biosensor having AChE immobilized onto MPs and stabilized through glutaraldehyde (GA) molecule was proposed for assay of the neurotoxic compounds. The prepared nanoparticles were modified by pure AChE and they were used for the measurement anti-Alzheimer’s drug galantamine and carbamate pesticide carbofuran with limit of detection 1.5 µM and 20 nM, respectively. All measurements were carried out using screen-printed sensor with carbon working, silver reference, and carbon auxiliary electrode. Standard Ellman’s assay was used for validation measurement of both inhibitors. Part of this work was the elimination of reversible inhibitors represented by galantamine from the active site of AChE. For this purpose, we used a lower pH to get the original activity of AChE after inhibition by galantamine. We also observed decarbamylation of the AChE-carbofuran adduct. Influence of organic solvents to AChE as well as repeatability of measurement with MPs with AChE was also established.

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Voltammetric assay of butyrylcholinesterase in plasma samples and its comparison to the standard spectrophotometric test

Cited by 29 publications

References 47 publications

Determination of acetylcholinesterase and butyrylcholinesterase activity without dilution of biological samples

Determination of acetylcholinesterase and butyrylcholinesterase activity without dilution of biological samples

Novel Enzymatic Potentiometric Approaches for Surfactant Analysis

Construction of an Acetylcholinesterase Sensor Based on Synthesized Paramagnetic Nanoparticles, a Simple Tool for Neurotoxic Compounds Assay

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