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)

Following the implantation of cobalt-gelatine pellets into the frontal cortex, epileptiform spikes in both primary and secondary foci developed and reached a peak between 7-12 days post implantation. Histological examination showed a necrotic lesion with terminal and fibre degeneration in brain areas connected with the frontal cortex. Golgi staining at 60 days showed a loss of pyramidal cells in the primary focal area. In the lesion and primary focal areas GABA, glutamate and aspartate were significantly reduced between 5--10 days post implantation. No changes in glutamine and glycine were found in either the lesion or pulmonary focus. No changes in amino acid content were found in the secondary focus or in glass implanted controls at any time. In cobalt-treated rats there were significant reductions in the transmitter related enzymes, glutamate decarboxylase, acetylcholinesterase, choline acetyltransferase and aromatic amino acid decarboxylase in the lesion area and primary and secondary foci at 4--8 days post implantation. Levels of these enzymes had recovered to normal by 24 days. Lactate dehydrogenase was reduced only in the lesion area. Beta-Galactosidase was reduced in the lesion area at 4 days but subsequent rose rapidly paralleling increasing gliosis around the lesion. It is concluded that cobalt-induced epilepsy is associated with relatively selective loss of neuronal tissue and provides a useful model for further investigation relevant to clinical epilepsy.
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PMID:Neurochemical and morphological changes during the development of cobalt-induced epilepsy in the rat. 113 20

The distribution of amino acids between plasma, liver and brain was studied in adult male rats, fed a diet containing 8.7, 17 (control animals), 32 and 51% of protein during 15 days. The caloric intake was nearly equal in all groups. The highest food intake was observed in the animals on the low protein diet. Changes in plasma amino acids were variable. In contrast to the behavior of most amino acids in plasma, the branched chain amino acids were highest in the animals fed the 51% protein diet. Despite the low protein intake in the animals fed a 8.7% protein diet, the concentration of serine, glutamic acid, glutamine, glycine, alanine, methionine, isoleucine, leucine, phenylalanine and ornithine were significantly higher compared to control animals, whereas in those receiving a high protein diet, valine, leucine, tyrosine, tryptophan and histidine increased in relation to the increased protein and amino acid intake. The plasma amino acid patterns are not greatly influenced by the amino acid distribution in the food and the amount ingested. Alanine aminotransferase, aspartate aminotransferase, glutamate dehydrogenase and cholinesterase showed a two- to fivefold increased activity in the liver of animals consuming a high protein diet. In the brain, the concentration of valine, leucine, isoleucine, phenylalanine and tyrosine in animals receiving the low protein diet was higher than in controls and increased further with increasing protein content of the diet. Glutamine was increased in all dietary groups. The predicted influx of amino acids showed increasing influx rates in dependence of the plasma amino acid concentration. The entry of tyrosine and tryptophan and their brain concentration was inversely proportional to the protein content of the diet. In the present study which considers long-term adaptation to an increasing protein and amino acid intake in comparison to a balanced control protein diet, the levels of the indispensable amino acids were maintained within narrow limits in the brain and liver. The results indicate that inspite of a variable protein intake, the body tends to keep organ amino acids in relatively narrow limits favoring in this way amino acid homeostasis.
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PMID:Effect of different protein diets on the distribution of amino acids in plasma, liver and brain in the rat. 159 Jun 69

Extracellular amino acid levels in CA3 and CA1 fields of rat hippocampus, an area highly sensitive to seizures, were determined by intracranial microdialysis during seizures induced by systemic administration of soman (o-1,2,2-trimethylpropyl methylphosphonofluoridate), a potent inhibitor of acetylcholinesterase. The glutamate uptake level was determined on another series of animals in hippocampus homogenates. An early and transient increase in the extracellular glutamate level occurred in CA3 within 30 min of seizures, with correlated brief elevations of taurine, glycine and glutamine levels. The glutamate level increased early in CA1, declined and then became more sustained (after 50 min of seizures). Apparent elevations of taurine, glycine and glutamine levels in CA1 accompanied changes in glutamate concentrations. Changes of glutamate level correlated with an increase in the glutamate uptake which rapidly declined after 40 min of seizures. The role of the transient release of glutamate in CA3 and of the sustained release in CA1 in prolonged soman-induced seizures is considered. The correlation between glutamate and other amino acid release is studied.
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PMID:Effects of soman-induced seizures on different extracellular amino acid levels and on glutamate uptake in rat hippocampus. 178 36

The histidine residue essential for the catalytic activity of pancreatic cholesterol esterase (carboxylester lipase) has been identified in this study using sequence comparison and site-specific mutagenesis techniques. In the first approach, comparison of the primary structure of rat pancreatic cholesterol esterase with that of acetylcholinesterase and cholinesterase revealed two conserved histidine residues located at positions 420 and 435. The sequence in the region around histidine 420 is quite different between the three enzymes. However, histidine 435 is located in a 22-amino acid domain that is 47% homologous with other serine esterases. Based on this sequence homology, it was hypothesized that histidine 435 is the histidine residue essential for catalytic activity of cholesterol esterase. The role of His435 in the catalytic activity of pancreatic cholesterol esterase was then studied by the site-specific mutagenesis technique. Substitution of the histidine in position 435 with glutamine, arginine, alanine, serine, or aspartic acid abolished the ability of cholesterol esterase to hydrolyze p-nitrophenyl butyrate and cholesterol [14C]oleate. In contrast, mutagenesis of the histidine residue at position 420 to glutamine had no effect on cholesterol esterase enzyme activity. The results of this study strongly suggested that histidine 435 may be a component of the catalytic triad of pancreatic cholesterol esterase.
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PMID:Site-specific mutagenesis of an essential histidine residue in pancreatic cholesterol esterase. 199 99

Myotubes prepared from the Japanese quail embryo at 9 days gestation were cultivated in the presence of glycyl-L-glutamine (Gly-Gln, beta-endorphin C-terminal dipeptide) or glycyl-glutamic acid (Gly-Glu), and changes in the activity of acetylcholinesterase (AChE) molecular forms and binding of 125I-alpha-bungarotoxin (alpha BGT) to cell surface nicotinic acetylcholine receptors were measured. The A12 oligomer was the major form of AChE in the cultures. The activity of all molecular forms of the enzyme was increased in the presence of Gly-Gln, but Gly-Glu did not alter AChE activity. In cells infected with the temperature-sensitive mutant, La31C, of Rous sarcoma virus (ts-RSV) and transferred to the nonpermissive temperature, the A12 form of AChE was absent, but its activity could be induced following exposure of the cells to Gly-Gln. When cells treated in this way were incubated in the presence of collagenase, there was a small but significant loss of A12 AChE activity, indicating that Gly-Gln stimulated the activity of a pool of this oligomer which was mainly but not entirely intracellular. Neither Gly-Gln nor Gly-Glu influenced 125I-alpha BGT binding after exposure of the cells to the peptides for any duration. Neither Gly-Gln nor Gly-Glu influenced the accumulation of cyclic AMP in the cultures. beta-Endorphin is one of a family of peptides that coexist transiently with acetylcholine in lower motoneurones of vertebrates in the perinatal period. This report provides evidence for the selective trophic activity of one of its derivatives toward the postsynaptic cholinergic system in avian muscle cells.
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PMID:Glycyl-L-glutamine stimulates the accumulation of A12 acetylcholinesterase but not of nicotinic acetylcholine receptors in quail embryonic myotubes by a cyclic AMP-independent mechanism. 215 12

The cholinesterases are serine hydrolases that show no global similarities in sequence with either the trypsin or the subtilisin family of serine proteases. The cholinesterase superfamily includes several esterases with distinct functions and other proteins devoid of the catalytic serine and known esterase activity. To identify the residues involved in catalysis and conferring specificity on the enzyme, we have expressed wild-type Torpedo acetylcholinesterase (EC 3.1.1.7) and several site-directed mutants in a heterologous system. Mutation of serine-200 to cysteine results in diminished activity, while its mutation to valine abolishes detectable activity. Two conserved histidines can be identified at positions 425 and 440 in the cholinesterase family; glutamine replacement at position 440 eliminates activity whereas the mutation at 425 reduces activity only slightly. The assignment of the catalytic histidine to position 440 defines a rank ordering of catalytic residues in cholinesterases distinct from trypsin and subtilisin and suggests a convergence of a catalytic triad to form a third, distinct family of serine hydrolases. Mutation of glutamate-199 to glutamine yields an enzyme with a higher Km and without the substrate-inhibition behavior characteristic of acetylcholinesterase. Hence, modification of the acidic amino acid adjacent to the serine influences substrate association and the capacity of a second substrate molecule to affect catalysis.
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PMID:Mutagenesis of essential functional residues in acetylcholinesterase. 221 85

Under anesthesia with sodium pentobarbital, the sciatic nerves of rats were transected bilaterally, and a catheter was inserted into the central end of the left renal artery. After an initial flush, an Alzet pump was attached to the catheter, containing various concentrations of glycyl-L-glutamine (Gly-Gln), methylprednisolone sodium succinate (MePred), or both. Rats were sacrificed at intervals of 2, 4, or 6 days; the peripheral portions of the sciatic nerves were excised, homogenized, and centrifuged, and the supernates were assayed for acetylcholinesterase (AcChoEase; acetylcholine acetylhydrolase, EC 3.1.1.7) and protein. Significantly higher contents of AcChoEase over untreated transected controls were obtained (i) at 4 days posttransection in rats infused with 0.015 M Gly-Gln and (ii) at 6 days posttransection in rats infused with MePred at 3.0 mg.kg-1.hr-1 after an initial dose of 120 mg/kg with or without Gly-Gln.
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PMID:Effects of glycyl-L-glutamine and methylprednisolone on maintenance of acetylcholinesterase of transected rat sciatic nerves. 225 Dec 90

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

Intracarotid infusion of 3 microM glycyl-L-glutamine was found to oppose the fall in the choline acetyl-transferase content of the preganglionically denervated cat superior cervical ganglion; this same effect has been demonstrated previously for acetylcholinesterase content. Because choline acetyltransferase, in contrast to acetylcholinesterase, occurs exclusively in the preganglionic axons and their terminals, this finding raises the possibility that glycyl-L-glutamine opposes postsectional axonal degeneration.
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PMID:Glycyl-L-glutamine opposes the fall in choline acetyltransferase in the denervated superior cervical ganglion of the cat. 260 63

Rats were given glycyl-L-glutamine (Gly-Gln) by intraaortic infusion with Alzet osmotic pumps during the 48-hr period following the intraaortic administration of diisopropyl phosphorofluoridate (DFP) (10 mumol/kg). The infusion of 1.2 mumol of Gly-Gln per 24 hr resulted in a significant increase in the acetylcholinesterase (AcChoEase; acetylcholine acetylhydrolase, EC 3.1.1.7) activity of the gastrocnemius muscles over that of rats that received DFP only. At a total dose of 3.6 mumol per 24 hr, a diminished result was obtained; at 0.36 mumol per 24 hr, no effect was detectable. These findings, together with earlier ones, suggest that the neurotrophic effect of Gly-Gln or a similar endogenous factor on AcChoEase synthesis is a general phenomenon at sites of cholinergic transmission.
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PMID:Effect of glycyl-L-glutamine on the rate of regeneration of acetylcholinesterase in the rat gastrocnemius muscle after diisopropyl phosphorofluoridate administration. 272 74


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