Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

1. Adult black ducks (Anas rubripes) were given freshwater or saltwater (1.5% NaCl) for 11 days and half of each group was also given an organophosphate (17 p.p.m. fenthion) in the diet on days 6-11. 2. After 11 days, ducks drinking saltwater had lost more weight and had higher plasma Na and uric acid concentrations and osmolalities than birds drinking freshwater. 3. Saltwater treatment stimulated the salt gland to increased weight and Na, K-ATPase activity. 4. Fenthion generally reduced plasma and brain cholinesterase activity and depressed cholinesterase and Na, K-ATPase activities in salt glands of birds drinking saltwater.
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PMID:Organophosphate inhibition of avian salt gland Na, K-ATPase activity. 612 65

To study the role of acetylcholine metabolism system in the mechanisms responsible for animals' resistance to emotional stress, the activity of acetylcholinesterase (AChE), butyrylcholinesterase and cholinacetyltransferase (CAT) was evaluated in brain structures and autonomous vegetative nervous system of rabbits after experimental emotional stress. In the course of experiments, arterial pressure and heart rate were recorded. The rabbits whose cardiovascular functions appeared to be resistant showed an increase in the activity of AChE and CAT in the perifocal area of the hypothalamus. It is suggested that the involvement of the perifocal area of the hypothalamus in the formation of the mechanisms responsible for the resistance is linked with the effects on water-salt metabolism.
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PMID:[Acetylcholinesterase and choline acetyltransferase in the nervous system of rabbits resistant to emotional stress]. 668 79

A direct and continuous kinetic method for the fluorimetric assay of various hydrolases by using new, highly water-soluble substrates is described. The latter consist of esters of strongly fluorescent 1-hydroxypyren-3,6,8-trisulfonic acid trisodium salt with acetic, butyric, caprylic, and oleic acid. Km and vmax values are given for the hydrolytic activity of porcine liver carboxylic ester hydrolase, wheat germ lipase, candida cylindracea lipase, hog kidney acylase I, and bovine pancreas alpha-chymotrypsin, while others (acetylesterase, trypsin, and cholinesterase) were studied qualitatively. By proper choice of the substrate, a fair selectivity may be achieved. Detection limits as low as 1 microgram enzyme/ml are found in some cases. Advantages of these new substrates over existing ones are briefly discussed.
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PMID:Fluorimetric assay of hydrolases at longwave excitation and emission wavelengths with new substrates possessing unique water solubility. 684 35

Extracts of the nematode Caenorhabditis elegans contain five molecular forms of acetylcholinesterase (AChE) activity that can be separated by a combination of selective solubilization, velocity sedimentation, and ion-exchange chromatography. These are called form IA (5.2s), form IB (4.9s), form II (6.7s), form III (11.3s), and form IV (13.0s). All except form III are present in significant amounts in rapidly prepared extracts and are probably native; form III is probably derived autolytically from form IV. Most of forms IA and IB can be solubilized by repeated extractions without detergent, whereas forms II, III, and IV require detergent for effective solubilization and may therefore be membrane-bound. High salt concentrations are not required for, and do not aid in, the solubilization of these forms. For all forms, molecular weights and frictional ratios have been estimated by a combination of gel permeation chromatography and velocity sedimentations in both H2O and D2O. The molecular weight estimates range from 83,000 to 357,000 and only form II shows extensive asymmetry. The separated forms have been characterized with respect to substrate affinity, substrate specificity, inhibitor sensitivity, thermal inactivation, and detergent sensitivity. Judging by these properties, C. elegans is like other invertebrates in that none of its cholinesterase forms resembles either the "true" or the "pseudo" cholinesterase of vertebrates. However, internal comparison of the C. elegans forms clearly distinguishes forms IA, III, and IV as a group from forms IB and II; the former are therefore designated "class A" forms, the latter "class B" forms. Genetic evidence indicates that separate genes control class A and class B forms, and that these two classes overlap functionally. Several factors, including kinetic properties, molecular asymmetry, molecular size, and solubility, all suggest that a molecular model of the multiple cholinesterase forms observed in vertebrate electric organs probably does not apply in C. elegans. Potential functional roles and subunit structures of the multiple AChE forms within each C. elegans class are discussed.
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PMID:Multiple molecular forms of acetylcholinesterase in the nematode Caenorhabditis elegans. 686 28

The anticholinesterase activity of the unsymmetric bisquaternary 6-aminoquinoline salt NSC-176319 (QB) was studied in vitro. QB proved to be a noncompetitive inhibitor of both acetylcholinesterase (or true cholinesterase) and butyrylcholinesterase (or pseudocholinesterase) having a KI = 0.5 X 10(-6) M for acetylcholinesterase and 1.5 X 10(-6) M for butyrylcholinesterase. Further, QB inhibited esterase activity of murine plasma in a noncompetitive manner (KI = 4.2 X 10(-6) M). The inhibition was instantaneous in onset and did not diminish with prolonged incubation of the drug and enzyme. All mice treated intravenously with 2 mg QB/kg died within 5 min. Prior to death, mice developed severe parasympathomimetic effects and convulsions. Although the parasympathomimetic effects were diminished by atropine sulfate pretreatment, death could only be prevented by barbiturate anesthesia.
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PMID:Anticholinesterase activity of the unsymmetric bisquaternary 6-aminoquinoline salt NSC-176319. 707 62

Several methods have been used to bind electric organ aetylcholinesterase to the walls of phosphatidylcholine liposomes. One of these methods [Brunner, J., Skrabal, P. & Hauser, H. (1976) Biochim. Biophys. Acta, 455, 322-331] achieved complete incorporation, although some enzyme was shown to be sequestered inside the vesicles. The association was established either in the presence of high salt media or altered liposomal membrane fluidity. The reconstitution process impaired the allosteric transition of acetylcholinesterase which is thought to occur when Flaxedil (gallamine triethiodide) is present in a low ionic strength medium. It is suggested that the cholinesterase is capable of being incorporated into liposomes, possibly via hydrophobic forces. Such a system may be an adequate one for further study of the functioning of the enzyme in a defined membrane environment.
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PMID:The incorporation of acetylcholinesterase from the electric organ into liposomes. 739 50

A simple, sensitive, and rapid colorimetric method is described for determining methyl parathion (O,O-dimethyl-O-p-nitrophenyl phosphorothioate) and methyl paraoxon (O,O-dimethyl-O-p-nitrophenyl phosphate), using p-nitrobenzene diazonium fluoroborate as the chromogenic salt. This colorimetric method is more sensitive than are other colorimetric methods based on non-enzymatic reactions. Pig liver acetone powder cholinesterase was found to be sensitive to methyl parathion. Inhibition can be detected at picogram levels, and 50-80 ng methyl paraoxon and 1-9 micrograms methyl parathion can be estimated.
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PMID:Colorimetric determination of methyl parathion and oxygen analog. 743 41

Bile-salt-activated lipase belongs to the cholinesterase alpha/beta-hydrolase-fold family of proteins. Here, we have investigated the structural organisation of the human isoform by mapping tryptic cleavage sites using limited proteolysis and by expression studies using a recombinant truncated variant. Two accessible regions in the tertiary structure were identified. The first is defined by a tryptic cleavage at Lys429 and lies within the alpha/beta-hydrolase fold in bile-salt-activated lipase between a central beta-sheet and an active-site histidine residue, as deduced from sequence similarity across the cholinesterases and known structural properties. This region exhibits a proteolytic and topological similarity to the lid region in pancreatic lipase. The other accessible region in the tertiary structure is defined by a tryptic cleavage at Arg520 and occurs within a catalytically non-essential segment Leu519-Gln535, as identified by expression of a truncated variant which lacks the C-terminus starting from Leu519. This region is consistent with an interdomain region between the cholinesterase-related part of the protein structure and the unique proline-rich C-terminal repeats. Both protease-sensitive regions appear to occur at domain borders, and, therefore, are consistent with a multi-domain structure. The truncated variant was fully functional as a lipase and as a bile-salt-stimulated esterase. However, compared to the full-length enzyme, the truncated variant showed an increased susceptibility to limited proteolysis, suggesting that the C-terminal repeats may regulate proteolytic degradation of the protein.
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PMID:Structural organisation of human bile-salt-activated lipase probed by limited proteolysis and expression of a recombinant truncated variant. 760 35

Monoclonal antibodies were raised against amphiphilic detergent-soluble (DS) acetylcholinesterase (AChE) from human brain caudate nucleus. Three mAb, 132-4 (IgG1), 132-5 (IgG1) and 132-6 (IgG3), specific for brain DS-AChE were selected and subcloned. These mAb reacted with native as well as heat-denatured and SDS-denatured DS-AChE, indicating that the epitopes to which mAb bound are continuous determinants. The mAb cross-reacted with DS-AChE from bovine and mouse brain and with brain DS-AChE from river trout (Salmo trutta forma fario) and lake trout (Salmo trutta forma lacustris). No cross-reaction was detected with the following antigens: salt-soluble (SS) AChE from bovine brain, glycophospholipid-anchored AChE from human and bovine erythrocytes, DS-butyrylcholinesterase and SS-butyrylcholinesterase (BtChE) from the brains of human and bovine, DS-BtChE from chicken and BtChE from human serum. Deglycosylation of brain DS-AChE with N-glycosidase F did not abolish the binding of mAb to DS-AChE. After reduction of brain DS-AChE by dithiothreitol, the mAb no longer reacted with the antigen, indicating that a disulfide bridge is important for the epitope. Monomerization of brain DS-AChE by trypsin and limited proteinase K treatment also abolished the binding of mAb to DS-AChE. Sucrose-density-gradient centrifugation showed that mAb reacted only with native tetrameric forms, but not with dimeric and monomeric forms. Western blot, after SDS/PAGE under non-reducing conditions, showed that mAb reacted with those subunits carrying the hydrophobic anchor (i.e. tetramers, trimers and heavy dimers) but not with those devoid of it (light dimers or monomers). Since mAb 132-4, 132-5 and 132-6 recognized DS-AChE from fish up to mammalian brain in the evolutionary tree, it is concluded that the epitope to which these mAb bind, is conserved in nature.
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PMID:Monoclonal antibodies against brain acetylcholinesterases which recognize the subunits bearing the hydrophobic anchor. 768 3

This study investigated the relationship between urinary sodium excretion and liver function, as assessed by the aminopyrine breath test (ABT) and conventional parameters, in 62 patients with cirrhosis kept on a constant salt diet. Urinary sodium excretion was related non-linearly to the ABT (r = 0.76). Less significant correlations were observed to the Child-Pugh score (r = -0.65), cholinesterase (r = 0.58), bilirubin (r = -0.56), albumin (r = 0.51) and prothrombin time (r = 0.49). When patients were arbitrarily divided into 6 groups according to the ABT, sodium excretion balanced the sodium intake up to a 50% reduction in ABT. In groups with more than a 50% reduction sodium retention occurred. When patients were grouped according to the Child-Pugh score, urinary salt output was balanced in patients with scores of 5 and 6 and decreased in patients with scores greater six. However, the change in sodium output from normal salt excretion to sodium retention was less pronounced in patients grouped according to the Child-Pugh score than in patients grouped according to the ABT. The results suggest a non-linear relationship between the impairment in hepatic and renal function in cirrhosis. They are compatible with the concept of a threshold of hepatic function necessary to maintain normal renal function.
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PMID:Relationship of the aminopyrine breath test and the Child-Pugh score to urinary sodium retention in patients with liver cirrhosis. 775 46


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