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)

Treatment of rats with aurantine for 7-30 days reduces the growth and development of animals, and especially of skeletal muscles. Low relative weight of muscles in aurantine-treated animals was accompanied by low resting and action membrane potentials. Incorporation of labelled uridine and lysine into muscles, heart, brain and liver was decreased. Retardation in the growth and development of skeletal muscles resulted into unfavourable shift of the ratio body weight/surface and led to prevalence of catabolic processes over anabolic ones (increased oxygen consumption, heart and respiration rate in experimental animals). These changes are probably related not only to the inhibition of protein synthesis, but to disturbance of regulatory mechanisms, which reveals itself in an increased norepinephrine content of the brain stem and in the increased cholinesterase activity in cardiac pacemaker.
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PMID:[Retardation of growth and development of rats induced by inhibition of protein synthesis at early postnatal ontogenesis]. 5 9

Human serum beta-lipoproteins, isolated by percipitation with heparin-calcium mixture, showed cholinesterase activity. The enzyme activity was almost proportional to the lipoprotein concentration. Rats, treated with neostigmine, a cholinesterase inhibitor, showed a significant decrease in serum beta-lipoprotein and in the incorporation of H3-lysine into the lipoprotein compared to untreated controls. The decreased incorporation of H3-lysine into beta-lipoprotein was associated with increased labelling of alpha-lopoprotein. There was no significant difference in the labelling of pre-beta-lipoprotein. We propose that LDL is formed from VLDL in the presence of cholinesterase.
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PMID:Serum cholinesterase: function in lipoprotein metabolism. 19 12

The purification and kinetic characterization of cholinesterase from blood plasma (pseudocholinesterase; butyrylcholinesterase: EC 3.1.1.8) is described. The hydrolysis of the artificial peptide substrate Lys-Pro-p-nitroanilide served as a model of the second step in degradation of substance P by dipeptidyl peptidase IV. The substrate is hydrolyzed by a gel-electrophoretic homogeneous cholinesterase preparation with a reaction rate of 5.8 mumol/min X mg and a KM value of 0.12 mmol/l. The proteolytic reaction could not be affected with typical cholinesterase inhibitors NaF and dibucain. On the other hand Lys (pNO2-Z)-Pro and a specific suicide substrate (diacylhydroxylamine derivative) inhibit the activity in a manner analogous to dipeptidyl peptidase IV. Though these active site-directed inhibitors also influenced the benzoylcholine hydrolyzing activity of serum cholinesterase, we conclude from the data that dipeptidyl peptidase IV was the true Lys-Pro-p-nitroanilide cleaving activity. Furthermore, the conclusion can also be drawn that hydrolysis of substance P reported by Lockridge 1982 is caused by the contamination that cannot be completely separated from the esterase during the purification method used.
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PMID:Contamination of highly purified human serum cholinesterase by dipeptidyl peptidase IV causing hydrolysis of substance P. 243 Mar 7

Primary cultures of hippocampal neurons are important for the study of trace elements in epileptogenesis. We developed a model system for culturing hippocampal neurons on poly-L-lysine in Iscove's modification of Dulbecco's MEM (IMDM) supplemented with K+, D-glucose, glutamine, insulin, p-amino benzoic acid, transferrin, BSA, beta-estradiol, gentamycin, and fungizone. Neurons were identified by histochemical staining for cholinesterase. Zinc at concentrations of 10(-9) to 10(-6) M induced metallothionein in hippocampal neuronal cultures. Maximum metallothionein induction occurred after 48 hrs incubation with zinc.
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PMID:Metallothionein induction in rat hippocampal neurons in primary culture. 251 54

The effect of chemical modification on the pseudocholinesterase and aryl acylamidase activities of purified human serum pseudocholinesterase was examined in the absence and presence of butyrylcholine iodide, the substrate of pseudocholinesterase. Modification by 2-hydroxy-5-nitrobenzyl bromide, N-bromosuccinimide, diethylpyrocarbonate and trinitrobenzenesulfonic acid caused a parallel inactivation of both pseudocholinesterase and aryl acylamidase activities that could be prevented by butyrylcholine iodide. With phenylglyoxal and 2,4-pentanedione as modifiers there was a selective activation of pseudocholinesterase alone with no effect on aryl acylamidase. This activation could be prevented by butyrylcholine iodide. N-Ethylmaleimide and p-hydroxy-mercuribenzoate when used for modification did not have any effect on the enzyme activities. The results suggested essential tryptophan, lysine and histidine residues at a common catalytic site for pseudocholinesterase and aryl acylamidase and an arginine residue (or residues) exclusively for pseudocholinesterase. The use of N-acetylimidazole, tetranitromethane and acetic anhydride as modifiers indicated a biphasic change in both pseudocholinesterase and aryl acylamidase activities. At low concentrations of the modifiers a stimulation in activities and at high concentrations an inactivation was observed. Butyrylcholine iodide or propionylcholine chloride selectively protected the inactivation phase without affecting the activation phase. Protection by the substrates at the inactivation phase resulted in not only a reversal of the enzyme inactivation but also an activation. Spectral studies and hydroxylamine treatment showed that tyrosine residues were modified during the activation phase. The results suggested that the modified tyrosine residues responsible for the activation were not involved in the active site of pseudocholinesterase or aryl acylamidase and that they were more amenable for modification in comparison to the residues responsible for inactivation. Two reversible inhibitors of pseudocholinesterase, namely ethopropazine and imipramine, were used as protectors during modification. Unlike the substrate butyrylcholine iodide, these inhibitors could not protect against the inactivation resulting from modification by 2-hydroxy-5-nitrobenzyl bromide, N-bromosuccinimide and trinitrobenzenesulfonic acid. But they could protect against the activation of pseudocholinesterase and aryl acylamidase by low concentrations of N-acetylimidazole and acetic anhydride thereby suggesting that the binding site of these inhibitors involves the non-active-site tyrosine residues.
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PMID:Chemical modification of the bifunctional human serum pseudocholinesterase. Effect on the pseudocholinesterase and aryl acylamidase activities. 286 42

The present investigation revealed the effect of the organochlorine insecticide dieldrin at the dose level 0.25 LD50 at different time intervals on the concentration of 11 rat brain amino acids, on the activities of glutamic oxyacetic transaminase (GOT), glutamic pyruvic transaminase (GpT) and cholinesterase. The study was also extended to include the total protein content during the tested periods. The daily injection of dieldrin caused a marked decrease in the levels of glutamic acid, glutamine and taurine and an increase in the levels of aspartic acid, asparagine, GABA, glycine, lysine, serine, alanine and histidine. However, the maximal increase and decrease were recorded for most of the tested amino acids at the end of the tested period. The activity of the transaminases increased significantly. The recorded values of GOT were usually higher than GPT. Cholinesterase activity was inhibited thoroughly during all the experimental periods. Total protein content was decreased in the experiment; the minimal value was given 3 days after the injection.
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PMID:Effect of dieldrin injection on the level of certain amino acids and some enzymes in rat brain. 287 4

Plasma levels of pipecolic acid, which is a minor metabolite of lysine, were determined by high-performance liquid chromatography in 22 patients with chronic liver disease, composed of 6 patients with chronic active hepatitis, 11 with liver cirrhosis and 5 with hepatocellular carcinoma. The plasma levels of pipecolic acid, when compared to those in normal subjects (1.00 +/- 0.08 nmoles per ml), were found to be significantly elevated (p less than 0.01) in patients with liver cirrhosis (1.93 +/- 0.24 nmoles per ml) and hepatocellular carcinoma (2.22 +/- 0.49 nmoles per ml), but did not show any significant change in patients with chronic active hepatitis. Plasma levels of pipecolic acid correlated positively with serum bile acid and bilirubin, and negatively with indocyanine green disappearance rate, cholinesterase and prothrombin time but not with plasma lysine levels. These results suggest that plasma levels of pipecolic acid increase almost parallel to the severity of liver damage, and that this increase in pipecolic acid may reflect the injury of liver peroxisomes which appear to be related to the degradation of pipecolic acid.
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PMID:Plasma levels of pipecolic acid in patients with chronic liver disease. 335 9

Cultures were prepared by dissociating 3-day-old whole chick embryos and plating the dispersed cells on poly-L-lysine-coated dishes in Dulbecco's Modified Eagle's Medium with 10% fetal calf serum. By 48 hr in culture, aggregates and neuritic sprouting were observed. Long neuritic bundles connecting cell aggregates were evident by 4 days in culture. Consistent patterns throughout the lifespan of the cultures were contacts between neurites, and flat isolated cells, presumptively glial, emerged. Throughout the lifespan of the cultures, the cholinergic cell population was characterized histochemically by the method of Karnovsky and Roots and biochemically by assaying choline acetyltransferase. By 4 days in culture, all aggregates showed light cholinesterase-positive staining; however, with days in culture, several aggregates had no staining, and some positive-stained aggregates were interconnected with other aggregates showing only spotted positive staining. Choline acetyltransferase activity showed a developmental profile in agreement with the histological findings. The early presence of choline acetyltransferase activity is taken as indication of the early commitment of cholinergic neurons.
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PMID:Growth patterns of primary cultures dissociated from 3-day-old chick embryos: morphological and biochemical comparisons. 376 86

1. It was recently proposed that acetylcholinesterase (AChE), in addition to its esteratic activity, has proteolytic activity such that it may cleave the beta-amyloid precursor (beta-APP) within the beta-amyloid sequence. The purpose of this paper was to examine further whether AChE or butyrylcholinesterase (BuChE) had associated proteinase activity that was involved in the metabolism of beta-APP. 2. The ability of various preparations of AChE and BuChE to hydrolyze two synthetic fragments of beta-APP695 as model substrates containing the normal and aberrant cleavage sites was studied. 3. Digestion of these synthetic substrates with commercial preparations of Electrophorus electricus AChE indicated the presence of a trypsin-like proteolytic activity cleaving each peptide at the carboxy-terminal side of an internal lysine residue. 4. Purification of the trypsin-like proteinase activity by aminobenzamidine affinity chromatography yielded a preparation that was devoid of AChE activity but retained all of the proteinase activity. 5. Amino-terminal sequence analysis of this preparation showed that the first 13 amino acid residues were identical to beta-pancreatic trypsin. 6. These data indicate that the proteinase activity found in these commercial preparations of AChE is due to contamination with trypsin.
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PMID:Proteolysis at the secretase and amyloidogenic cleavage sites of the beta-amyloid precursor protein by acetylcholinesterase and butyrylcholinesterase using model peptide substrates. 824 91

In search of the molecular mechanisms underlying the broad substrate and inhibitor specificities of butyrylcholinesterase (BuChE), we employed site-directed mutagenesis to modify the catalytic triad residue Ser198, the acyl pocket Leu286 and adjacent Phe329 residues, and Met437 and Tyr440 located near the choline binding site. Mutant proteins were produced in microinjected Xenopus oocytes, and Km values towards butyrylthiocholine and IC50 values for the organophosphates diisopropylfluorophosphonate (DFP), diethoxyphosphinylthiocholine iodide (echothiophate), and tetraisopropylpyrophosphoramide (iso-OMPA) were determined. Substitution of Ser198 by cysteine and Met437 by aspartate nearly abolished activity, and other mutations of Ser198 completely abolished it. Tyr440 and Leu286 mutants remained active, but with higher Km and IC50 values. Rates of inhibition by DFP were roughly parallel to IC50 values for several Leu286 mutants. Both Km and IC50 values increased for Leu286 mutants in the order Asp < Gln < Lys. In contrast, cysteine, leucine, and glutamine mutants of Phe329 displayed unmodified Km values toward butyrylthiocholine, but up to 10-fold decreased IC50 values for DFP, iso-OMPA, and echothiophate. These findings add Tyr440 and Phe329 to the list of residues interacting with substrate and ligands, demonstrate plasticity in the active site region of BuChE, and foreshadow the design of recombinant BuChEs with tailored scavenging properties.
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PMID:Site-directed mutagenesis of active site residues reveals plasticity of human butyrylcholinesterase in substrate and inhibitor interactions. 829 37


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