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)

Human brain acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) were sequentially extracted, first with a Tris-saline buffer (S1) and then with 1% (w/v) Triton X-100 (S2). About 20 and 30% of the AChE and BuChE activities were recovered in S1 and most of the remaining enzymes in S2. Main molecular forms of about 10.5 S and 12.0 S, G4 forms of AChE and BuChE, and smaller amounts of 4.5 S and 5.5 S forms, G1 species of AChE and BuChE, were measured in S1. Application of Triton X-114 phase partitioning and affinity chromatography on phenyl-agarose to S1 revealed that 25% of the AChE and none of the BuChE molecules displayed amphiphilic properties. Analysis of the enzyme activity retained by the phenyl-agarose showed that G1 AChE constituted the bulk of the amphiphilic molecules released without detergent. Main G4 forms of AChE and BuChE were found in the S2 extract. Eighty and 45% of the AChE and BuChE activities in S2 were measured in the detergent-rich phase by Triton X-114 phase partitioning. Thus, most of the AChE and about half of the BuChE molecules in S2 displayed amphiphilic properties. The main peak of BuChE, a 12.0 S form in gradients made with Triton X-100, splits into two peaks of 9.5 S and 12.5 S in Brij 96-containing gradients. This suggests that hydrophilic G4 BuChE forms are predominant in S1 and that hydrophilic and amphiphilic isoforms coexist in S2.
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PMID:Amphiphilic and hydrophilic forms of acetyl- and butyrylcholinesterase in human brain. 841 Dec 69

The G2 form of butyrylcholinesterase (BChE) of mucosal cells of rat intestine is a rare amphiphilic species, which is related to class II of acetylcholinesterase. Preliminary work indicated that the enzyme can bind heparin and suggested particular properties as compared to other BChEs. Ionic properties of the G2 form BChE were studied with different ionic exchangers. Heparin-Sepharose chromatography, nondenaturing electrophoresis and sucrose gradient centrifugation were used to study heparin interaction with the G2 form BChE. The enzyme structure was modified with reagents that react specifically with amino groups (p-hydroxyphenylglyoxal and 2,4,6-trinitrobenzene sulfonic acid). The G2 form was not retained by DEAE-cellulose which was generally used to isolate BChE from human serum, but was completely bound by strong cation exchanger (Dowex 50). Heparin-Sepharose quantitatively retained the enzyme which was partially eluted only by charged compounds. Nondenaturing gel electrophoresis showed a reduction in enzyme migration with increasing concentrations of heparin and chondroitin sulfate, but not with heparan sulfate. Triton X-100 dissociated the G2 form into monomers but failed to reverse the association between the enzyme and heparin. Reagents specific to amino groups indicated that arginine and lysine residues were involved in this association. In summary, these studies demonstrate that the ionic properties of the G2 form BChE are involved in the binding with heparin. Our results rule out the possibility of amphiphilic interactions in the formation of heparin-enzyme complex and indicate that amino groups are predominately involved in this association.
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PMID:Electrostatic interactions of the butyrylcholinesterase dimer of mucosal cells of rat intestine with glycosaminoglycans. 869 3

Specimens of astrocytoma, oligodendroglioma and medulloblastoma were sequentially extracted with saline and saline-Triton X-100 buffers. Acetyl- (AChE) and butyrylcholinesterase (BuChE) activities were assayed in the soluble fractions, these being further analyzed to establish the distribution of molecular forms. All the tumors tested showed AChE and BuChE activities, the measured AChE/BuChE ratios being unrelated to the malignant grading. Hydrophilic and amphiphilic AChE and BuChE tetramers, amphiphilic AChE dimers and monomers, and hydrophilic BuChE monomers were identified in all the tumors analyzed. The amphiphilic behavior of the enzyme forms was assessed by sedimentation analysis and hydrophobic chromatography on phenyl-Agarose. A small fraction of glioma AChE monomers was released as, or transformed into, hydrophilic forms by incubation with phosphatidylinositol-specific phospholipase C (PIPLC). These data suggest that AChE monomers bearing distinct hydrophobic domains coexist in human glioma.
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PMID:Molecular forms of acetyl- and butyrylcholinesterase in human glioma. 871 Jan 79

In searching for possible differences in the composition of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) forms in dystrophic brain, the distribution of various enzyme molecules in normal (NB) and dystrophic (DB) 129B6F1/J mouse brain has been investigated. The tissue was sequentially extracted with saline (S1) and with saline-Triton X-100 buffers (S2) to release soluble and membrane-bound cholinesterases. About 15% of the AChE and 35% of the BuChE activities in NB were recovered in S1, and the rest in S2. G4, G2, and G1 AChE and BuChE forms were identified in the soluble fractions obtained from NB and DB. The shift in sedimentation values of the separated AChE and BuChE species in sucrose gradients made with and without detergents revealed the occurrence of hydrophilic (H) and amphiphilic (A) variants of cholinesterases in the extracts. The amphiphilic properties of the several AChE and BuChE molecules were analyzed by Triton X-114 phase-partitioning and by phenyl-agarose chromatography. A12 (1%), G4A (72%), G4H (8%), and G2A + G1A (19%) AChE molecules, and G4A (34%), G4H (19%), and G2A + G1A (47%) BuChE forms, were identified in NB. The G4A AChE and BuChE isoforms differed in their interaction with Triton X-114 and with a hydrophobic matrix. Neither the extent of cholinesterase solubilization, nor the distribution of individual enzyme forms, was significantly altered in DB. The lack of specific differences in the distribution of AChE and BuChE forms between NB and DB suggests that the biosynthetic pathway leading to the various enzyme forms is altered in muscle but not in dystrophic mouse brain.
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PMID:Molecular forms of acetyl- and butyrylcholinesterase in normal and dystrophic mouse brain. 882 Sep 70

The structural properties of acetyl-(AChE) and butyrylcholinesterase (BuChE) in meningioma and the possible relationship with brain and plasma were investigated. Meningioma ChEs were extracted with saline and saline-Triton X-100 buffers. The tumor ChE forms were identified by sedimentation analysis, and their amphiphilic/hydrophilic behaviour was assessed by Triton X-114 phase-partitioning and hydrophobic chromatography. Meningioma contained amphiphilic globular AChE dimers (G2A) and monomers (G1A), and hydrophilic BuChE tetramers (G4H). The conversion of G2A into G1A AChE by reduction confirmed their structures. In contrast to the meningioma species, brain G1A AChE forms remained amphiphilic after incubation with alkaline hydroxylamine and phosphatidylinositol-specific phospholipase C (PIPLC). Meningioma G1A and PIPLC-converted G1H, and brain G1A AChE showed similar rate constants for thermal inactivation, and this suggested that the thermal stability of AChE subunits was unaffected by the presence or not of phosphatidylinositol residues. AChE in meningioma and brain did not differ in the interaction with the lectins Con A, LCA, WGA and RCA. BuChE in meningioma and brain bound to a similar extent to Con A, LCA and WGA-Agarose, whereas one-half of BuChE in the tumor, all in plasma and little in brain was fixed by RCA. Therefore, meningioma possesses RCA(+)- and RCA(-)-BuChE, the former predominating in brain and the latter in plasma. It remains to be clarified whether the tumor RCA(+)-BuChE is intrinsic or derived from plasma.
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PMID:Biochemical properties of acetyl- and butyrylcholinesterase in human meningioma. 898 37

The influence of non-ionogenic surfactants, i.e., Tween-20, Triton X-100 and PEG-10,000, on the response of cholinesterase-based potentiometric biosensors and their sensitivity towards reversible and irreversible inhibitors were investigated. Acetyl- and butyrylcholinesterases were immobilized on nylon, cellulose nitrate films and tracing paper and were introduced into an assembly of potentiometric biosensors. The effect of surface-active compounds depends on the hydrophilic properties and porosity of the enzyme support material and the inhibition mechanism. In the range 0.002-0.3% m/v the surfactants show a reversible inhibiting effect on biosensor response. At lower concentrations (down to 10(-4)% m/v) the surfactants alter the analytical characteristics of reversible and irreversible inhibitor determination. The use of surface-active additives improves the biosensor selectivity in multi-component media.
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PMID:Influence of surface-active compounds on the response and sensitivity of cholinesterase biosensors for inhibitor determination. 900 8

It has been shown that benzethonium chloride produces linear mixed-type inhibition of choline esterase and acetylcholine esterase. These enzymes also show-reagent-carry-over inhibition if the enzyme activities are measured in plastic cuvettes in which previously protein has been determined by the alkaline benzethonium chloride method. Choline esterase is about 10-fold more sensitive to benzethonium chloride than acetylcholine esterase. With acetylthiocholine as substrate Michaelis-Menten constants for choline esterase and acetylcholine esterase are 85 mumol/l and 102 mumol/l, respectively. Carry-over inhibitory effect of benzethonium chloride can be avoided by washing the cuvettes, after protein determination by the benzethonium chloride method, with 5 ml/l Triton X-100, 5 ml/l Tween 20 or 10 g/l sodium dodecyl sulphate. The latter has a disadvantage in that it precipitates out at low temperatures. The dry slide method (Johnson & Johnson) for serum choline esterase is free of the inhibitory effect until the concentration of benzethonium chloride in the sample reaches about 200 mumol/l.
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PMID:Inhibition of acetylcholine esterase and choline esterase by benzethonium chloride and avoidance of the benzethonium chloride carry-over inhibitory effect. 929 50

A single form of cholinesterase was detected in the parasitic nematode Parascaris equorum and purified from a low-salt Triton X-100 extract of whole animals by affinity chromatography on an edrophonium-Sepharose matrix. Based on gel-filtration chromatography, sedimentation analysis and SDS-PAGE, such a cholinesterase is an amphiphilic globular (G2) dimer (125-129 kDa, 6.1 S). It includes some hydrophobic domain other than phosphatidylinositol, which gives autoaggregation, detergent interaction and also anchors the molecule to the cell membrane. The enzyme, probably functional in cholinergic neurotransmission, is an acetylcholinesterase showing a fairly low substrate specificity with thiocholine esters. Electrostatic interactions seem to play a major role in the catalytic activity. Studies with inhibitors gave complete inhibition with 1 mM eserine, low sensitivity for procainamide and for tetra(monoisopropyl)pyrophosphortetramide as well as higher inhibition with edrophonium chloride and 1,5-bis(4allyldimethylammoniumphenyl)-pentan-3-one dibromide. The enzyme also showed excess-substrate inhibition with acetylthiocholine. No cross-hybridization occurred between the gene(s) encoding acetylcholinesterase in P. equorum and ace-1 from the free-living nematode Caenorhabditis elegans. The expression of a single cholinesterase form in P. equorum, unusual in free-living nematodes, could be due to parasitic life adaptation with resulting reduction of locomotor activity.
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PMID:Expression of a single dimeric membrane-bound acetylcholinesterase in Parascaris equorum. 948 77

The effect of non-ionic detergents like Triton X-100, Lubrol PX, Brij 35 and Tween 80 on the esterase activity and inhibitor sensitivity of human serum butyrylcholinesterase (BuChE) were studied. The results showed that though BuChE is not a detergent dependent enzyme, the esterase activity and inhibitor sensitivity of it can be modulated by the presence of detergents. All the detergents caused a marginal activation of the esterase activity. The presence of Lubrol PX, Brij 35 or Tween 80 did not affect the 50% molar inhibition concentration (IC50) of the inhibitors tested. But in the presence of Triton X-100 the IC50 values were increased for neostigmine, eserine and tetraisopropylpyrophosphoramide (acylation site interacting inhibitors), whereas for inhibitors like ethopropazine, imipramine and procainamide (choline binding pocket specific inhibitors) the IC50 values were unaltered. In addition, in the presence of Triton X-100 the bimolecular reaction constant for phosphorylation reaction (ki) of BuChE for the acyl pocket specific tetraisopropylpyrophosphoramide was reduced. Triton X-100 partially protected BuChE against this tetraisopropylpyrophosphoramide inactivation. These results indicate that Triton X-100 by interacting with the acyl pocket hydrophobic region is able to activate the esterase activity of BuChE. Further it reduces the capacity of the enzyme to react with inhibitors that inactivate it by interacting with the serine residue of the acylation site.
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PMID:Interaction of Triton X-100 with acyl pocket of butyrylcholinesterase: effect on esterase activity and inhibitor sensitivity of the enzyme. 980 62

We have previously determined that Nippostrongylus brasiliensis secretes three monomeric nonamphiphilic (G1na) variants of acetylcholinesterase (AChE) with broadly similar properties. In this study we have examined AChE expression in somatic extracts of N. brasiliensis and report the identification of an additional enzyme which is not secreted. The enzyme was resolved by sucrose density gradient centrifugation with a sedimentation coefficient of 10.2 S which was shifted to 9.4 S in the presence of Triton X-100, identifying the enzyme as a tetrameric amphiphilic (G4a) form. The amphiphilic properties of this enzyme were confirmed by charge-shift electrophoresis, in which migration was accelerated by interaction with sodium deoxycholate. The enzyme showed low activity with butyrylthiocholine, and a Michaelis constant of 91 +/- 13 microM for acetylthiocholine was determined. It was highly sensitive to the AChE-specific inhibitor bis (4-allyldimethylammoniumphenyl)pentan-3-one dibromide, with an IC50 of 6.5 +/- 0.4 microM, but was also inhibited by the butyrylcholinesterase-specific inhibitor tetramonoisopropylpyrophosphortetramide, albeit with a higher IC50 of 46.5 +/- 6.1 microM. This enzyme can therefore be distinguished from the secreted AChEs by its amphiphilic properties, sedimentation in sucrose gradients, and sensitivity to cholinesterase inhibitors.
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PMID:Nippostrongylus brasiliensis: characterisation of a somatic amphiphilic acetylcholinesterase with properties distinct from the secreted enzymes. 999 Mar 42


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