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)

Gene expression in chorionic villi may be particularly vulnerable to environmental exposure to poisonous substances. To reveal villus gene products which are thus subject to poisoning, molecular cloning was employed. A single sample of apparently normal chorionic villi (approximately 40 mg, from 9 weeks' gestation) was microscopically dissected to ensure purity of fetal tissue. Total RNA was extracted by isothiocyanate and directly employed for reverse transcription. A chorionic villus cDNA library was constructed from this preparation in the phage vector lambda gt10 and contained 60,000 independent recombinants. In the present study, this cDNA library was screened with labelled cDNA probes encoding human butyrylcholinesterase (BCHE) and acetylcholinesterase (ACHE). Nine BCHEcDNA clones were isolated out of 1.6 x 10(6) phages (5.7 x 10(-6) of screened recombinants) and exhibited similar restriction patterns to those observed for BCHEcDNA from other human tissues. In contrast, no ACHEcDNA clones could be found in 4.0 x 10(6) screened phages (less than 2.5 x 10(-6) of recombinants). These findings demonstrate efficient transcription (similar to fetal brain levels) from the BCHE gene but not from the ACHE gene in chorionic villi, and support the notion that BCHE is involved in chorionic villus growth and development.
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PMID:Chorionic villus cDNA library displays expression of butyrylcholinesterase: putative genetic disposition for ecological danger. 172 78

The total cholinesterase activity in canine tracheal smooth muscle was found to consist of butyrylcholinesterase and acetylcholinesterase in a ratio of 3:1. Most of the acetyl- and butyrylcholinesterase sites were distributed on the muscle surface; the remaining hydrolytic sites were associated with internal structures. Intracellular acetylcholinesterase staining was associated with the perinuclear envelope, sarcoplasmic reticulum and Golgi apparatus. Intracellular butyrylcholinesterase was associated with the perinuclear envelope, sarcoplasmic reticulum and the contractile filaments. Inhibition of acetylcholinesterase by the selective agent 1,5,bis(allyl-dimethylammoniumphenyl)-pentane-3-one dibromide (BW 284C51) led to a parallel leftward shift in the concentration-response curve for bath-applied acetylcholine. A similar shift was observed in the frequency-response curve for neurally released acetylcholine. Inhibition of butyrylcholinesterase by the selective agent tetraisopropyl-pyrophosphoramide potentiated the response to bath-applied and neurally released acetylcholine; the potentiation was limited to acetylcholine concentrations greater than or equal to 1 microM and frequencies greater than or equal to 10 Hz. It is concluded that both acetyl- and butyrylcholinesterase participate in the hydrolysis of acetylcholine in canine tracheal smooth muscle. The role of acetylcholinesterase is evident over the entire range of concentrations (1 nM to 100 microM) and frequencies (1 to 90 Hz) examined, whereas the role of butyrylcholinesterase is confined to the higher end of the concentration and frequency ranges used.
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PMID:Function and distribution of acetyl- and butyrylcholinesterase in canine tracheal smooth muscle. 172 68

The expression of the neural crest cell (NCC) markers acetylcholinesterase (AChE) and the HNK-1-epitope is compared from the emigration of cephalic NCC until the formation of the cranial nerves V-X in chicken and quail hindbrain. We show that NCC transiently express acetylcholinesterase (AChE) activity during their emigration; NCC migrate into butyrylcholinesterase (BChE)-positive areas of the cranial mesenchyme. Along these migratory tracks that foreshadow the course of later projecting cranial nerves, BChE increases strongly in cells that may represent immature Schwann cells. Both AChE and BChE, but not HNK-1, are expressed in the ectodermal placodes. In NCC, HNK-1 is expressed strongly only when they approach their destination sites. Their intense expression of HNK-1 then leads to the establishment of tunnel-shaped HNK-1 matrices, within which G4-positive cranial neurites begin to extend. We conclude that AChE and HNK-1 expression in cephalic NCC serve different functions, since AChE is related to their migration, and HNK-1 to their aggregation and the formation of an extracellular neurite scaffold.
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PMID:Cranial nerve growth in birds is preceded by cholinesterase expression during neural crest cell migration and the formation of an HNK-1 scaffold. 172 28

1. The activity and the molecular characteristics of butyrylcholinesterase were studied in the epithelial cells of the following intestinal segments: duodenum, jejunum, ileum, caecum and colon of starved and refed rats. 2. After starvation, the specific activity of the enzyme is found to increase in the jejunum. The same level of activity was maintained after refeeding. No notable changes were observed in the other intestinal segments after either starvation or refeeding. 3. The behaviour of aminopeptidase, a well-characterized intestinal enzyme, is comparable to that of butyrylcholinesterase, except in the duodenum where the aminopeptidase activity is increased after refeeding. 4. In this cell type, BuChE is found only in its globular forms (G1, G2 and G4). Starvation resulted in a higher value of the sedimentation coefficient of the ileal G2 form, suggesting the existence of a complex between the enzyme and non-cholinesterase components. 5. After refeeding, the sedimentation profile was similar to that of control.
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PMID:Behaviour of butyrylcholinesterase in the intestinal epithelial cells of starved and refed rats. 173 92

Two para-dialkylaminobenzenediazonium salts, the dimethylamino (A) and dibutylamino (B) derivatives, are presented as structural probes for acetylcholinesterase and butyrylcholinesterase. While being reversible competitive inhibitors in the dark, A and B behave, upon irradiation and through the formation of arylcation species, as irreversible labels of ammonium-binding sites of both enzymes. The observed variations of the different inactivation rate constants point to a different structural environment for acetylcholinesterase-binding and butyrylcholinesterase-binding sites. Moreover, in the case of acetylcholinesterase, protection experiments with specific ligands (edrophonium and propidium) showed that the dimethylamino salt A exclusively labels the hydrolytic anionic site, whereas the dibutylamino salt B also labels the peripheral site. Specificities and stoechiometries of the incorporations were determined and, in the case of acetylcholinesterase, the irradiated protein was submitted to chemical degradation. Peptide maps were obtained by gel-permeation chromatography and HPLC, giving access to labelled peptides which belong either to the active or to the peripheral site.
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PMID:Photoaffinity labelling of cholinesterases. Discrimination between active and peripheral sites. 173 32

Human tissues have two distinct cholinesterase activities: acetylcholinesterase and butyrylcholinesterase. Acetylcholinesterase functions in the transmission of nerve impulses, whereas the physiological function of butyryl-cholinesterase remains unknown. An atypical form of butyrylcholinesterase or the absence of its activity leads to prolonged apnea following administration of the muscle relaxant suxamethonium. Inheritance of these butyrylcholinesterase variants is consistent with the enzyme activity being encoded in a single autosomal locus, BCHE (formerly CHE1 and E1), which has been assigned to chromosome 3. Previous in situ hybridization of a BCHE cDNA probe gave evidence of homologous sequences at 3q26 and 16q11-q23, raising the possibility of more than one locus coding for butyrylcholinesterase [H. Soreq, R. Zamir, D. Zevin-Sonkin, and H. Zakut (1987) Hum. Genet. 77: 325-328]. Using a different cDNA probe hybridized in situ to 46,XX,inv(3)(p25q21) metaphase chromosomes, we report here the localization of BCHE to a single autosomal location: 3q26.
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PMID:The cloned butyrylcholinesterase (BCHE) gene maps to a single chromosome site, 3q26. 176 57

A simple method for the separate determination of acetylcholinesterase and butyrylcholinesterase activities in amniotic fluid is reported. This determination is performed with an enzyme electrode involving an immobilized choline oxidase membrane associated with the amperometric detection of hydrogen peroxide. Acetylcholine or butyrylcholine, in the presence of samples containing acetylcholinesterase or butyrylcholinesterase are specifically hydrolyzed, the formation of choline being detected vs time by the sensor with no need for a selective inhibitor. The dynamic linear ranges for acetylcholinesterase and butyrylcholinesterase are respectively 100 microU to 10 mU and 30 microU to 3 mU per ml sample.
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PMID:Rapid and sensitive discriminating determination of acetylcholinesterase activity in amniotic fluid with a choline sensor. 177 89

The epithelial cells of the human intestine exhibit a cholinesterase activity which is restricted to the apex of the villi. This activity displays a maximum in the colon and a minimum in the jejunum. Contrary to most of the studied vertebrates, the human cells present both acetylcholinesterase and butyrylcholinesterase activities, acetylcholinesterase being predominant in all the intestinal segments: duodenum, jejunum, ileum and colon. Like in the other vertebrates, only globular forms are identified by sucrose gradient centrifugation. However, the simultaneous presence, on the one hand of three globular forms (G1, G2 and G4) and, on the other hand of soluble as well as detergent-soluble molecular species seems to be a particular feature of the human cells.
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PMID:Human intestine epithelial cell acetyl- and butyrylcholinesterase. 177 60

We report Raman spectra of various cholinesterases: lytic tetrameric forms (G4) obtained by tryptic digestion of asymmetric acetylcholinesterase (AChE) from Torpedo californica and Electrophorus electricus, a PI-PLC-treated dimeric form (G2) of AChE from T marmorata, and the soluble tetrameric form (G4) of butyrylcholinesterase (BuChE) from human plasma. The contribution of different types of secondary structure was estimated by analyzing the amide I band, using the method of Williams. The spectra of cholinesterases in 10 mM Tris-HCl (pH 7.0) indicate the presence of both alpha-helices (about 50%) and beta-sheets (about 25%), together with 15% turns and 10% undefined structures. In 20 mM phosphate buffer (pH 7.0), the spectra indicated a smaller contribution of alpha-helical structure (about 35%) and an increased beta-sheet content (from 25 to 35%). This shows that the ionic milieu profoundly affects either the conformation of the protein (AChE activity is known to be sensitive to ionic strength), or the evaluation of secondary structure, or both. In addition, we analyzed vibrations corresponding to the side chains of aromatic and aliphatic amino acids. In particular, the analyses of the tyrosine doublet (830-850 cm-1) and of the tryptophan vibration at 880 cm-1 indicated that these residues are predominantly 'exposed' on the surface of the molecules.
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PMID:A comparative Raman spectroscopic study of cholinesterases. 179 30

The toxic effects of the organophosphorus pesticide methylparathion are primarily caused by the inhibition of acetylcholinesterase activity in the central nervous system, whereas the relationship between butyrylcholinesterase and poisoning symptoms is unclear. The presumed different effects of methylparathion on acetylcholinesterase in various regions of brain and spinal cord suggest differences in the distribution of molecular enzyme forms. In the present work, the in vitro and in vivo effects of methylparathion on acetylcholinesterase and butyrylcholinesterase were studied in whole brain homogenates of golden hamsters with biochemical methods. Furthermore, acetylcholinesterase activity was determined in regions of the nervous system by quantitative histochemistry (microdensitometry). Biochemically, very low IC50 values of the hydrophilic and lipophilic fractions of both enzymes were measured. Analysis of the time course of enzyme inhibition revealed maximum inhibition 45 min after methylparathion application. Using microdensitometry different degrees of acetylcholinesterase inhibition were found in various areas of the brain. The highest inactivation was observed in the Substantia nigra and in thalamic nuclei; in several regions of the cerebellum, the inhibition rate was comparatively lower. In conclusion, methylparathion acts as an potent inhibitor of acetylcholinesterase and butyrylcholinesterase in the hamster nervous system. The region-specific different inactivation of acetylcholinesterase might be caused by the existence of multiple forms of the enzyme in various brain regions.
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PMID:Inhibition of acetylcholinesterase and butyrylcholinesterase by the organophosphorus insecticide methylparathion in the central nervous system of the golden hamster (Mesocricetus auratus). 180 11


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