Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.1.8 (cholinesterase)
 12,691 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This paper reviews our previously published data and presents new results on biosensor assay of blood esterases. Tyrosinase and choline oxidase biosensors based on nanostructured polyelectrolyte films were developed for these purposes. Experiments were performed on the quantitative determination of acetylcholinesterase (AChE), butyrylcholinesterase (BChE), carboxylesterase (CaE), and neuropathy target esterase (NTE) in samples of whole blood of rats, mice, and humans. Good agreement was found between biosensor and spectrophotometric assays for AChE, BChE, and CaE. No direct comparison could be made for NTE because its activity cannot be measured spectrophotometrically in whole blood. A new method of simultaneous quantitative determination of AChE and BChE in test mixtures is also described. This method represents a bifunctional biosensor for the simultaneous analysis of choline and phenol based on integration of individual sensors. Algorithms for calculation of separate concentrations of AChE and BChE in the mixture were developed. The mean error of calculated component concentrations was approximately 6% for binary test mixtures. The present work provides a foundation for building multiplexed systems for the simultaneous determination of multiple esterases with applications to biomonitoring for exposures to organophosphorus compounds.
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PMID:Biosensor analysis of blood esterases for organophosphorus compounds exposure assessment: approaches to simultaneous determination of several esterases. 2009 86

This work examines the adsorption regime and the properties of microgel/enzyme thin films deposited onto conductive graphite-based substrates. The films were formed via two-step sequential adsorption. A temperature- and pH-sensitive poly(N-isopropylacrylamide)-co-(3-(N,N-dimethylamino)propylmethacrylamide) microgel (poly(NIPAM-co-DMAPMA microgel) was adsorbed first, followed by its interaction with the enzymes, choline oxidase (ChO), butyrylcholinesterase (BChE), or mixtures thereof. By temperature-induced stimulating both (i) poly(NIPAM-co-DMAPMA) microgel adsorption at T > VPTT followed by short washing and drying and then (ii) enzyme loading at T < VPTT, we can effectively control the amount of the microgel adsorbed on a hydrophobic interface as well as the amount and the spatial localization of the enzyme interacted with the microgel film. Depending on the biomolecule size, enzyme molecules can (in the case for ChO) or cannot (in the case for BChE) penetrate into the microgel interior and be localized inside/outside the microgel particles. Different spatial localization, however, does not affect the specific enzymatic responses of ChO or BChE and does not prevent cascade enzymatic reaction involving both BChE and ChO as well. This was shown by the methods of electrochemical impedance spectroscopy (EIS), atomic force microscopy (AFM), and amperometric analysis of enzymatic responses of immobilized enzymes. Thus, a novel simple and fast strategy for physical entrapment of biomolecules by the polymeric matrix was proposed, which can be used for engineering systems with spatially separated enzymes of different types.
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PMID:Engineering Systems with Spatially Separated Enzymes via Dual-Stimuli-Sensitive Properties of Microgels. 2653 39

Based on choline oxidase immobilized by co-crosslinking on an overoxidised polypyrrole modified platinum electrode, a novel electrochemical assay for cholinesterase activity in human serum was developed. The assay was performed by adding an aliquot of cholinesterase standard solution or serum sample to phosphate buffer containing choline or thiocholine ester and measuring the oxidation current of hydrogen peroxide at the rotating modified electrode polarized at +0.7 V vs. SCE. The influence of some experimental parameters such as pH of the assay, mass transport at the electrode, type and concentration of the cholinesterase substrate was studied and optimised. Reversible inhibition of choline oxidase from cholinesterase substrates was evidenced for the first time, which increases in the order of acetylcholine, butyrylcholine and s-butyrylthiocholine. Wide linear range, fast response time and appreciable long-term stability were assured for both acethyl- and butyrylcholinesterase assays. On allowing the polypyrrole layer to efficiently remove interferences from the electroactive compounds in the sample, the present method revealed to be suitable for the detection of butyrylcholinesterase in human serum at activities as low as 0.5 U L-1. The validation with a reference spectrophotometric method showed no significant differences when human serum samples were analysed.
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PMID:Assay of serum cholinesterase activity by an amperometric biosensor based on a co-crosslinked choline oxidase/overoxidized polypyrrole bilayer. 2936 80


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