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)

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

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

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

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 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

In continuation of previous studies, the intraarterial fusion of L-glutamic acid for 24 hr was found to oppose the decrease in acetylcholinesterase and butyrylcholinesterase in the superior cervical ganglion of the cat that otherwise occurs 48 hr after preganglionic denervation. The combination of glutamic acid and gamma-aminobutyric acid, in concentrations that were inactive individually, likewise produced the same neurotrophic effect. Inactive in this respect were glycine plus L-glutamine, pyroglutamic acid, gamma-aminobutyric acid, and L-aspartic acid. The possible mechanisms and implications of these findings are discussed.
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PMID:L-glutamic acid, a neurotrophic factor for maintenance of acetylcholinesterase and butyrylcholinesterase in the preganglionically denervated superior cervical ganglion of the cat. 345 34

Intracarotid infusion of glycyl-L-glutamine (Gly-Gln) was shown previously to oppose the fall in the acetylcholinesterase and butyrylcholinesterase contents of the cat superior cervical ganglion (SCG) that otherwise follows preganglionic denervation. However, its effect was demonstrable only on the vascularly remote left SCG but not on the directly infused right SCG. Accordingly, it was concluded that a metabolite of Gly-Gln, formed in the blood, is an active neurotrophic factor. Glycyl-L-glutamic acid and L-glutamic acid were subsequently found to have a similar but less marked effect on both SCG. In the present study an alternative explanation has been tested: that Gly-Gln must combine slowly with some component of plasma to enable it to penetrate the ganglion cells and exert its neurotrophic effect. Findings are consistent with the latter proposal.
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PMID:Direct neurotrophic action of glycyl-L-glutamine in the maintenance of acetylcholinesterase and butyrylcholinesterase in the preganglionically denervated superior cervical ganglion of the cat. 347 18

The authors presented the results of a study of enzymuria (cholinesterase, gamma-glutamine transferase, alkaline phosphatase, beta-galactosidase and lactate dehydrogenase with separate determination of N- and M-subunits) in 20 patients with a mixed form of glomerulonephritis (GN), 36 with the nephrotic form of GN and 13 patients with the hematuric form of GN. The clinical importance of the determination of enzymatic activity in the urine in GN of children lies in the recognition of the degree of damage of the glomerular filter as well as the nephrothelium. Basing on enzymuria pathophysiological syndromes found in various combinations in the above forms of GN were identified. Three degrees of damage of the permeability of the glomerular filter were defined for high molecular proteins. Differences in individual values of the activity of some enzymes gave rise to differential-diagnostic coefficients as well as differential-diagnostic tables which could be used for differential diagnosis between the GN mixed and nephrotic forms.
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PMID:[Clinical significance of enzymuria in glomerulonephritis in children]. 376 57

L. W. Haynes and M. E. Smith have reported [(1985) Biochem. Soc. Trans. 13, 174-175] that glycyl-L-glutamine (Gly-Gln) increases the A12 and G4 forms of acetylcholinesterase (AcChoEase) in cultured embryonic rat skeletal muscle. Since Gly-Gln meets the criteria established for the neurotrophic factor (NF) in extracts of central nervous system/sciatic nerves that maintains AcChoEase and butyrylcholinesterase (BtChoEase) in the denervated cat superior cervical ganglion (SCG) in vivo, it was tested by the latter procedure. Solutions of Gly-Gln (10(-7)-10(-3) M) in 0.9% NaCl solution were infused for 24 hr via the right common carotid artery of cats with preganglionically denervated SCG, following ligation of the external carotid and lingual arteries. At 48 hr postdenervation, the AcChoEase and BtChoEase contents of the right SCG were within the range of similarly treated controls infused with 0.9% NaCl solution; the AcChoEase and BtChoEase contents of the left SCG, where the infused solutions arrived by way of a much more circuitous route, were significantly elevated at concentrations of Gly-Gln of 10(-5) M and higher. This suggested that the neurotrophic effect on the left SCG was produced by a metabolite of Gly-Gln. Accordingly, glycine, L-glutamine, and glycyl-L-glutamic acid (Gly-Glu) were then tested. Glycine and L-glutamine were inactive; Gly-Glu, 10(-6)-10(-5) M, exerted a significantly positive neurotrophic effect at both the right and left SCG; at 10(-4) M, the effect was absent. The method employed currently for preparation of extracts of SCG for assay of AcChoEase, BtChoEase, and protein contents (homogenization of scissor-minced ganglia in water) was compared with homogenization in molar NaCl/1% Triton X-100. Values obtained by the former procedure, in comparison with the latter, were 91% +/- 7% for AcChoEase and 83% +/- 7% for BtChoEase, expressed as substrate hydrolyzed per mg of protein per min.
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PMID:Glycyl-L-glutamine, a precursor, and glycyl-L-glutamic acid, a neurotrophic factor for maintenance of acetylcholinesterase and butyrylcholinesterase in the preganglionically denervated superior cervical ganglion of the cat in vivo. 386 Aug 56

The pathology and enzymology of the intestinal mucosae of lambs dosed daily with 2500 Trichostrongylus vitrinus larvae and killed at five, nine or 14 weeks were compared with worm-free animals. The proximal small intestines of the infected lambs exhibited extensive mucosal damage at five and nine weeks, but only isolated lesions were found at 14 weeks. Activities of the brush border enzymes alkaline phosphatase, leucine amino-peptidase, maltase and glycyl-L-leucine dipeptidase were all significantly depleted during infection, although the magnitude, time of onset and duration of the individual enzyme responses varied. Mucosal activities of the pancreatic enzymes, trypsin and to a lesser extent chymotrypsin were also markedly decreased particularly during the first nine weeks of infection. Specific acetylcholinesterase activity was significantly increased throughout the study, maximal levels being observed at five weeks. In contrast 'pseudo'-cholinesterase levels were consistently within the control range. During the early stages of infection (five weeks) glutamine-oxaloacetate transaminase activity was significantly decreased, while aldolase and creatine phosphokinase levels were significantly elevated. At nine weeks low glutamine-oxaloacetate transaminase activities were again detected and lactate dehydrogenase activity was also markedly reduced. At 14 weeks the mean activities of all four enzymes were within the normal range as were superoxide dismutase levels throughout. Significant correlations were found between alkaline phosphatase, trypsin, chymotrypsin, aldolase and glutamine-oxaloacetate transaminase activities and the degree of mucosal damage within the individual lambs.
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PMID:Changes in the intestinal enzyme activity of lambs during chronic infection with Trichostrongylus vitrinus. 710 Jun 47


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