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

A potentiometric method for cholinesterase inhibitor analysis based on mediatorless bioelectrocatalysis has been developed. The method includes coimmobilization of three enzymes, butyrylcholinesterase, choline oxidase and peroxidase, on composite carbon electrodes. Catalytic hydrolysis of butyrylcholine and subsequent catalytic oxidation of choline result in the formation of hydrogen peroxide leads to a shift in the electrode potential. The detection limit for trichlorfon analysis is 2 x 10(-13) M. Electrodes remain stable for at least 4 weeks when stored at 277 K.
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PMID:Potentiometric biosensors for cholinesterase inhibitor analysis based on mediatorless bioelectrocatalysis. 868 64

To determine the basal acetylcholine level in the dialysate of rat frontal cortex, a horseradish peroxidase-osmium redox polymer-modified glassy carbon electrode (HRP-GCE) was employed instead of the conventional platinum electrode used in high-performance liquid chromatography-electrochemical detection (HPLC-ED). In initial experiments, an oxidizable unknown compound interfered with the detection of basal acetylcholine release on HPLC-HRP-GCE. An immobilized peroxidase-choline oxidase precolumn (pre-reactor) was included in the HPLC system, to eliminate the interference from the unknown compound. This combination could detect less than 10 fmol of standard acetylcholine and basal acetylcholine levels in the dialysate from a conventional concentric design microdialysis probe, without the use of cholinesterase inhibitor, and may facilitate physiological investigation of cholinergic neuronal activity in the central nervous system.
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PMID:Detection of basal acetylcholine release in the microdialysis of rat frontal cortex by high-performance liquid chromatography using a horseradish peroxidase-osmium redox polymer electrode with pre-enzyme reactor. 883 37

A method of DNA immobilization on cellulose nitrate films has been developed. Modified films of uniform and stable surface have been used to devise two variants of solid-phase enzyme immunoassays of antibodies. The co-immobilization of enzyme label (cholinesterase) and the DNA molecules makes it possible to carry out the procedure of solid-phase enzyme immunoassay without any separation of components. Thus, it takes only 15 min to diagnose an autoimmune disease (Aleutian disease of minks) with the immunoenzyme amperometric sensor, with a lower detection limit for antibodies of 0.5 x 10(-10) M. For scaled diagnosing, solid-phase enzyme immunoassay on DNA-modified films with prior separation of components and spectrophotometric registration of peroxidase activity has been developed. The time for determination was 30 min, with a lower detection limit of 7.4 x 10(-12) M.
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PMID:New variants of enzyme immunoassay of antibodies to DNA. 891 84

Selective amperometric enzyme microsensors for monitoring low micromolar concentrations of choline in extracellular fluid of rat brain have been developed. Preparation of the choline microsensors involved the modification of carbon fiber microcylinder electrodes (10 microns diameter, 300-400 microns long) with a cross-linked redox-active gel containing horseradish peroxidase and choline oxidase. Rejection of the noise recorded from the choline microsensors implanted in living brain tissue improved the in vivo detection capabilities of the sensors. The microsensors and a differential detection scheme were used to estimate the basal concentration of choline in striatal tissue at 6.6 +/- 2.9 microM and to measure changes in choline concentrations of 6.1 +/- 2.7 microM in vivo. The microsensors were also used to monitor choline produced following the injections of acetylcholine in vivo. Coinjections of neostigmine and acetylcholine significantly lowered the choline response recorded with the microsensors, confirming that the response following the injections of acetylcholine alone was due to the activity of endogenous acetylcholinesterase. Comparison of the maximal rate of decrease in choline concentration following the injections of 1 mM choline and 1 mM acetylcholine was used to estimate the rate of acetylcholine clearance from extracellular fluid through cholinesterase activity at approx. 2.5 microM/min.
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PMID:Amperometric microsensors for monitoring choline in the extracellular fluid of brain. 898 84

Lactoperoxidase, when incubated with increasing amounts of promethazine (P) and promethazine sulfoxide (PO) catalyzes the formation of promethazine sulfoxide accompanied by oxygen consumption. An intermediate radical of PO can be detected by electron spin resonance (ESR). Catalase or superoxide dismutase do not inhibit the reaction while dopamine does. The lactoperoxidase-catalyzed formation of dopaminochrome in the presence of hydrogen peroxide is inhibited by P. Both P and PO inhibit acetyl- and butyrylcholinesterase. Purified enzymes were used throughout the study and horseradish peroxidase but not myeloperoxidase had an activity similar to that of lactoperoxidase.
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PMID:A peroxidase-catalyzed sulfoxidation of promethazine. 951 66

Potentiometric choline electrodes were developed on the basis of the mediator-free bioelectrocatalysis. The electrodes made of a composite carbon-polymer material contain choline oxidase and peroxidase coimmobilized on the surface of the electrode. The rate of the potential increase was shown to be proportional to the choline concentration within a broad range of variation. Coupling of choline-sensitive electrodes with butyrylcholinesterase makes possible both the direct detection of butyrylcholine and analysis of butyrylcholinesterase inhibitors.
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PMID:[Potentiometric electrodes for determining choline, butyrylcholine and cholinesterase inhibitors]. 964 13

The cell populations in the dorsal motor nucleus of the vagus (DMNV) of the rat were studied by light microscopy and transmission electron microscopy, including retrograde labeling with horseradish peroxidase and histochemical demonstration of the distribution of the activity of the enzymes acetylcholinesterase (AcChE) and butyrylcholinesterase (BuChE). Two types of neurones were observed: 1) Larger Type A cells, which stain for both AcChE and BuChE and which project into the vagus nerve trunk, and 2) smaller Type B cells, which stain lightly for AcChE but not for BuChE and which do not project into the vagus nerve. Standardised vagal crush at the mid-cervical level causes loss of cholinesterase activity in Type A neurones within a few days but has no effect on Type B neurones. Changes in nuclear morphology of Type A neurones are pronounced at 10 weeks postinjury, indicating that degeneration is irreversible even by this stage. The number of Type A cells projecting to the vagus nerve reduces as a function of time, presumably as these cells die. Only a small number of Type A neurones persist at 2 years postinjury.
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PMID:Ultrastructural and cytochemical study of neurones in the rat dorsal motor nucleus of the vagus after axon crush. 976 28

Neutrophil function in 40 workers occupationally exposed to carbamate and organophophate insecticides were examined and compared to those of non-exposed individuals. Phagocytosis and intracellular killing of Candida albicans and Candida pseudotropicalis by neutrophils were studied. Two species of Candida were used since in individuals with myeloperoxidase deficiency neutrophils are unable to kill Candida albicans, while Candida pseudotropicalis can be effectively lysed. Phagocytosis of both antigens was normal in all the workers studied. On the other hand, there was a considerable reduction in the ability of neutrophils from exposed workers to kill Candida albicans whereas Candida pseudotropicalis was effectively lysed. This finding indicates some interference with the myeloperoxidase activity in the exposed population. The levels of cholinesterase activity in all workers were normal. These results demonstrate that exposure to carbamates and organophophates insecticides may lead to changes in neutrophil function even in workers presenting no impairment in the cholinesterase activity.
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PMID:Neutrophil function in workers exposed to organophosphate and carbamate insecticides. 1040 34

Reactive phosphonate diesters were designed and prepared as inhibitors of serine proteases and esterases. Inactivation of trypsin, chymotrypsin, and butyrylcholinesterase was determined by residual enzymatic activity as well as by the release of a chromogenic or fluorogenic product of the inhibition reaction. Second-order rate constants were determined from rates of nitrophenol formation. Application of the reaction for active-site titration of enzyme preparations is demonstrated. A basic functional group present in the nitrophenyl tropane phosphonate diester was shown to confer selectivity for inactivation of trypsin and chymotrypsin. Biotinylated derivatives of the phosphonate diesters were prepared to permit analysis of proteins modified in the inhibition reaction. Labeled polypeptides were resolved by SDS-PAGE, electroblotted, and detected by streptavidin-peroxidase staining. A detection limit of less than 4 ng, corresponding to 20 nM of trypsin, was demonstrated. Pretreatment of enzymes with DFP or nonbiotinylated phosphonates specifically blocks the labeling. This technique permits identification of serine proteases in complex mixtures with good sensitivity and specificity.
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PMID:Inhibition and labeling of enzymes and abzymes by phosphonate diesters. 1082 63

Qing Nao Yi Zhi Fang (QNYZ), a traditional Chinese medicine, has been developed as a drug to be used for the prevention and treatment of vascular dementia. However, the mechanisms by which this drug affects vascular dementia remain unknown. We examined the effects of QNYZ serum on glutamate excitotoxicity in rat fetal cerebral neuronal cells in primary culture. Exposure of neuronal cells to glutamate leads to a decrease in the activities of cholinesterase, superoxide dismutase, and streptoavidin peroxidase, and an increase in lactate dehydrogenase release. These enzyme activities were restored to the levels in untreated cells by the addition of QNYZ serum. QNYZ serum suppressed the increased nitric oxide production induced by glutamate and prevented glutamate-mediated apoptosis. QNYZ serum also improved mitochondrial energy metabolism after glutamate exposure. These findings suggest that QNYZ has protective effects against glutamate-mediated excitotoxicity in neuronal cells during ischemic brain injury.
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PMID:Effects of a traditional Chinese medicine, Qing Nao Yi Zhi Fang, on glutamate excitotoxicity in rat fetal cerebral neuronal cells in primary culture. 1092 65


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