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:3.1.1.7 (acetylcholinesterase)
28,390 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A population of vesicles 150 +/- 30 nm in diameter was isolated from banked human blood and the perturbation of their membrane studied. SDS polyacrylamide gel electrophoresis revealed the complete loss of spectrins from the vesicle membrane which was also depleted of various intrinsic proteins. In particular, severe reduction of protein 3 and glycophorin is consistent with the over 80% decline of intramembrane particles in either fracture face of the vesicle membrane. The stimulation of vesicle acetylcholinesterase is considered indicative of an initial disintegration associated with the segregation and rearrangement of membrane constituents. The findings are discussed with regard to the subcellular mechanisms of erythrocyte vesiculation.
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PMID:Erythrocyte vesiculation. 2. Membrane molecular transformation. 617 May 53

Electron spin resonance, enzymatic, and SDS-polyacrylamide gel electrophoretic investigations of erythrocyte membranes from patients with Alzheimer's disease were performed. Alterations in the physical state of membrane proteins in Alzheimer's disease erythrocytes were found by spin labeling studies. However, no alterations in membrane lipid fluidity or in the activities of membrane-bound sodium plus potassium-stimulated, magnesium-dependent adenosine triphosphatase or acetylcholinesterase could be demonstrated. Also, no changes in staining profiles of AD erythrocyte membrane proteins subjected to electrophoresis were observed. The altered conformation and/or organization of extraneural membrane proteins in Alzheimer's disease suggests the possibility that this disorder may have more widespread membrane involvement than was originally thought.
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PMID:Spin label and biochemical studies of erythrocyte membranes in Alzheimer's disease. 624 87

Immunohistochemical reactions were conducted, using the antibodies against GFA and S-100 proteins on sections of cerebellum from the homozygous (jj) and the heterozygous (Jj) Gunn rats. Hypertrophy of the fibrous astrocytes was observed but hyperplasia of the glial cells was not. Although the molecular layer was very thin, the Bergmann fibre appeared normal. Among the free amino acids in the cerebellum from the jj rat, glutamate concentration decreased to two-thirds of the control level. The protein profile of the cerebellum from the jj rat obtained by SDS-polyacrylamide gel electrophoresis revealed that the amount of P400 protein that is characteristic of Purkinje cells decreased considerably and there were also some changes of the other unidentified proteins. By two-dimensional electrophoresis, it was observed that in the supernatant from the jj rat cerebellum one protein spot diminished and in the particulate fraction from the jj rat one spot was enormously increased. The activity of 2',3'-cyclic nucleotide 3'-phosphohydrolase (CNPase) in the cerebellum from the jj rat did not differ significantly from that of the control; however, activities of choline acetyltransferase and acetylcholinesterase of the jj rat were about twice as high as those of the control. 2-Deoxyglucose incorporation was maximum in the granular layer from both the jj and the Jj rat cerebella. However, the incorporation in the jj cerebellum was not higher than in the Jj control and even lower in some parts of the jj cerebellum than in the control Jj cerebellum.
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PMID:Cerebellar hypoplasia in the Gunn rat with hereditary hyperbilirubinemia: immunohistochemical and neurochemical studies. 625 97

The light and heavy smooth-surfaced membranes (LSM and HSM), which had densities corresponding to 1.08 M and 1.28 M sucrose, respectively, were isolated from rat brain and some of their biochemical properties were investigated. Both LSM and HSM showed high Na+,K+-ATPase activity and, in particular, in HSM the activity was four times (21.55 mumol/mg protein/h) higher than that of the brain homogenate. High 2',3'-cyclic nucleotide 3'-phosphodiesterase activity (293.4 mumol/mg protein/h) was characteristic of LSM. 5'-Nucleotidase and acetylcholinesterase activities were also higher in LSM than in HSM. SDS-polyacrylamide gel electrophoresis showed that LSM and HSM had many protein component and that low molecular weight proteins such as proteolipid protein and basic protein were almost absent, in contrast with myelin and myelin-like membrane. GM1 ganglioside constituted the major class of total ganglioside in both LSM and HSM. These biochemical findings suggested that LSM is a membrane that has not previously been described, or a membrane fraction related to the oligodendroglial plasma membrane.
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PMID:Further studies on the smooth-surfaced membranes isolated from rat brain. 625 69

Bungarus multicinctus venom was fractionated into its toxin components using ion-exchange chromatography on CM-Sephadex. According to previous reports, rechromatography of fraction II on a CM cellulose column yields chemically homogenous alpha-bungarotoxin (II2) of molecular weight 9000. However, in our hands, using the identical purification procedure, two discrete proteins of molecular weight 9000 and 15,000 were obtained as demonstrated by SDS gel electrophoresis. Subsequent fractionation of this alpha-bungarotoxin fraction (II2) was achieved on Sephadex G-50. The 9000 weight component (labelled II-S2) was identical to alpha-bungarotoxin; at a concentration of 1 microgram/ml it blocked transmission at the neuromuscular junction but did not block nicotinic responses in rat sympathetic ganglia. Very different properties were exhibited by II-SI, the 15,000 molecular weight component; it inhibited ganglionic transmission but was ineffective at the neuromuscular junction at the same concentration (1 microgram/ml). BGT II-S1 was equipotent in blocking the ganglionic action potential in the presence or absence of eserine; thus, it is not acting as an acetylcholinesterase by increasing acetylcholine breakdown. In the presence of toxin, [3H]choline incorporation into ganglionic acetylcholine during preganglionic stimulation was not altered, suggesting that the toxin did not block transmission by a presynaptic mechanism. Thus, the site of action of the toxin appears to be postsynaptic although it did not affect depolarization of the ganglia induced by carbachol.
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PMID:Blockade of transmission in rat sympathetic ganglia by a toxin which co-purifies with alpha-bungarotoxin. 628 99

Incubation of washed rabbit platelets with suspensions of dilauroylglycerophosphocholine resulted in the shedding of vesicles without causing any appreciable leakage of cytoplasmic marker (lactate dehydrogenase) or organelle marker [( 14C]serotonin). The response was dependent on incubation time, concentration of dilauroylglycerophosphocholine and reaction temperature. Vesicles were separated from platelets and exogenous dilauroylglycerophosphocholine by a series of centrifugation steps. An average diameter of vesicles was 100-200 nm on scanning electron microscopy. Vesicles were enriched 5-fold in plasma membrane marker enzyme, acetylcholinesterase, whereas specific activities of lactate dehydrogenase and intracellular membrane marker enzyme, NADH-cytochrome c reductase were decreased in vesicles. Protein analysis by SDS-polyacrylamide gel electrophoresis showed that actin and actin-binding protein were present, while myosin was barely detectable in vesicles. Vesicles contained all phospholipid species of intact platelets and cholesterol but almost 50% of phospholipids in vesicles was dilauroylglycerophosphocholine. The phospholipid to protein ratio in vesicles was about 6.5-times higher than in intact platelets.
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PMID:Vesiculation of platelet plasma membranes. Dilauroylglycerophosphocholine-induced shedding of a platelet plasma membrane fraction enriched in acetylcholinesterase activity. 649 86

Separation of the external membranes from freshly converted mechanical schistosomula of Schistosoma mansoni was achieved by osmotic shock under hypertonic conditions, followed by mechanical shearing and ultracentrifugation. Prior to treatment, the schistosomula were surface labeled by introduction of N-DNP-epsilon-aminocaproylphosphatidylethanolamine molecules into their lipid bilayer followed by anti-DNP antibodies and stained with either 125I-protein-A or ferritin labeled secondary anti-DNP antibodies. This label provided a membrane marker by which the purity of the preparation could be assessed at each stage. Fluorescence staining with FITC-conjugated secondary antibodies prior to treatment revealed that the homogeneously stained membrane of the intact schistosomula became swollen and ruptured after the osmotic shock. The isolated membrane pellet was intensely fluorescent. Electron microscopical examination revealed mostly vesicles, some of them with organized multilayer assembly. The vesicles were ferritin labeled, indicating that they originated from the outer surface membrane of the schistosomula. A 100 fold enrichment in the alkaline phosphatase activity and about 300 fold enrichment in acetylcholinesterase activity in the membrane preparations, as compared to the intact schistosomula, was found. The isolated tegument was analyzed by SDS-polyacrylamide gel electrophoresis. The pattern obtained showed three major bands, of molecular weights 69 000, 45 000 and 12 000 alongside with a large number of minor bands. Immunoprecipitation of the isolated 125I-labeled membrane antigens with antisera from chronically infected mice revealed these three major bands together with three other bands of molecular weight 38 000, 23 000 and 16 000.
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PMID:Isolation and partial characterization of the tegumental outer membrane of schistosomula of Schistosoma mansoni. 652 92

A single direct injection of a local anesthetic, 0.5% bupivacaine hydrochloride (BPVC) (Marcaine), into rat soleus and extensor digitorum longus (EDL) muscles produced massive fiber necrosis with extensive phagocytosis followed by rapid regeneration, predominantly in the soleus. Since the sarcoplasmic reticulum (SR) was functionally disturbed by BPVC administration as confirmed by an in vitro study, the sarcolemmal lysis seen in the early phase of degeneration was not assumed to simply result from direct damage to the plasma membrane caused by BPVC. The extracellular fluid containing a high concentration of calcium (Ca) ions then permeated into the sarcoplasm through the defective membrane resulting in hyper-contracted myofibrils. Selective damage to the Z-line, an early sign of muscle degeneration, was shown by electron microscopy and SDS gel electrophoresis (preferential loss of alpha-actinin). Administration of leupeptin, a thiol protease inhibitor, proved to be ineffective in inhibiting the necrotic process, because the BPVC induced muscle fiber breakdown was probably too acute and fulminant to demonstrate the inhibitory effect upon the degenerative process. Well preserved satellite cells, peripheral nerves, and acetylcholinesterase activity, and the absence of fibrous tissue proliferation in this system may be responsible for the extremely rapid regeneration with complete muscle fiber type differentiation. Since the sequence of fiber breakdown induced by BPVC administration was similar to that of progressive muscular dystrophy, this chemical will be one of the most useful tools for studying the pathophysiology of fiber necrosis and regeneration in diseased muscle.
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PMID:Pathophysiology of muscle fiber necrosis induced by bupivacaine hydrochloride (Marcaine). 661 29

[3H]Diisopropylfluorophosphate was used to label covalently the catalytic subunits of the acetylcholinesterase forms extracted using different solubilization media. The incorporation of radiolabel was specific for true acetylcholinesterase, and SDS-polyacrylamide gel electrophoresis revealed that differences in molecular size existed between low salt-soluble (mol. wt. approximately 76 000), detergent-soluble (69 000) and high salt-soluble (72 000) acetylcholinesterase. These differences could not be attributed solely to an unusual migration behaviour but appeared to reflect differences in primary structure. While the basic unit of the low salt-soluble esterase was a monomer, the detergent-soluble esterase was linked by disulphide bridges to form dimers. The high salt-soluble form existed in large aggregates, whereby disulphide bridges form covalent links between the catalytic and non-catalytic elements. Pronase treatment showed that the differences were confined to the 'outer' structure of these molecules. The active site peptide exhibited homologies indicating that this part is conserved in the different classes of acetylcholinesterase. The results suggest that one can discriminate between at least three distinct esterase classes in the electric organ of Torpedo marmorata.
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PMID:Structural differences in the catalytic subunits of acetylcholinesterase forms from the electric organ of Torpedo marmorata. 664 20

In normal whole human blood in vitro, the source of the enzyme controlling the hydrolysis of aspirin (ASA) was found to be the erythrocyte (RBC). Experiments were carried out to determine whether this enzyme was membrane-bound or free in the lysate. The mean rates of ASA hydrolysis in comparable concentrations of intact RBC (1.61 +/- 0.20 mumole/liter/minute, n = 12 and 1.23 +/- 01.7 mumole/liter/minute, n = 5) were much faster than that measured in isolated RBC membranes (0.23 +/- 0.08 mumole/liter/minute, n = 6, P = less than 0.001). Detailed study showed that the RBC-related ASA esterase is located intracellularly and is not related to membrane acetylcholinesterase. The ASA esterase from crude lysate was purified 900-fold by means of DEAE Sephacel chromatography of active enzyme recovered from a 50% saturated ammonium sulfate fraction. Non-SDS polyacrylamide gel electrophoresis (pH 8.3 and 9.0) resulted in one major band and one or more small minor protein bands. When esterase activity was assayed in a non-stained gel, ASA depletion and salicylate production corresponded exactly to the major stained band. This band was eluted from another unstained gel, concentrated, and applied to an SDS gel. This yielded a single band with a molecular weight of approximately 95,000. The partially purified enzyme had a mean Km of 66.6 +/- 3.5 microM and a mean Vmax of 4.0 +/- 0.9 mumole/liter/minute/mg under the assay conditions. The results of inhibition studies suggested that this enzyme's activity is sulfhydryl group dependent, does not require divalent cations for activity, and is different from the RBC type D "nonspecific" esterases.
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PMID:Identification and partial purification of the major aspirin hydrolyzing enzyme in human blood. 683 77


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