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)

The effects of tacrine (5 mg/kg i.p.), a potent acetylcholinesterase inhibitor, were studied in rats pretreated (24 h beforehand) with a single dose (12 mEq/kg i.p.) of LiCl. Tacrine and LiCl were ineffective when given individually. Tacrine elicited seizures and brain damage in 90% of the rats treated. The intracerebroventricular microinfusion of N omega-nitro-L-arginine methyl ester (300 micrograms given 24 h after LiCl administration) significantly reduced the seizures and brain damage produced by tacrine (given 15 min later). These experiments suggest that the seizures and brain damage elicited by tacrine may be due, in part, to increased nitric oxide production in the brain.
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PMID:Tacrine-induced seizures and brain damage in LiCl-treated rats can be prevented by N omega-nitro-L-arginine methyl ester. 132 16

1. The enzymatic, hemorrhagic, procoagulant and anticoagulant activities of venoms of some animals including snakes, lizards, toads, scorpions, spider, wasps, bees and ants were compared. 2. Snake venom was the richest source of enzymes among the animal venoms. Most other animal venoms were devoid of phosphodiesterase, L-amino acid oxidase, alkaline phosphomonoesterase and acetylcholinesterase activities and only a few exhibited arginine ester hydrolase activity. These venoms, however, exhibited wide ranges of protease, 5'-nucleotidase and hyaluronidase activities. Most of the animal venoms examined exhibited some phospholipase A activity. 3. Other than snake venoms, only venoms of the toad Bufo calamita and the lizards were hemorrhagic, and only venoms of the social wasps, social bees and harvester ant exhibited strong anticoagulant activity. Procoagulant activity occurs only in snake venoms.
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PMID:Comparative study of the enzymatic, hemorrhagic, procoagulant and anticoagulant activities of some animal venoms. 136 Mar 87

Some biological and neurochemical properties of the venom of stonefish (Syanceja horrida) were investigated. The venom exhibited oedema-inducing, haemolytic, hyaluronidase, thrombin-like, alkaline phosphomonoesterase, 5' nucleotidase, acetylcholinesterase, phosphodiesterase, arginine esterase, and arginine amidase activities. Recalcification clotting time, prothrombin, and kaolin-cephalin clotting times were increased 1.7-2.3- and 2.4-fold respectively. The LD50 (i.v. mouse) was 300 micrograms/Kg. Its effects on uptake and stimulation of neurotransmitter synthesis and release were observed in rat brain synaptosomes. In the presence of 100 micrograms venom, uptake of [methyl-3H] choline in rat brain synaptosomes was inhibited 70%, while that of 4-amino-n-[U-14C] butyric acid was inhibited 20%. The toxin also stimulated the release of [3H]-acetylcholine from the synaptosomes.
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PMID:Biological activities of Synanceja horrida (stonefish) venom. 136 68

The crystal structure of fasciculin 1, a potent acetylcholinesterase inhibitor from green mamba snake venom, has been solved by the multiple isomorphous replacement method complemented with anomalous scattering and subsequently refined at 1.9-A resolution. The overall structure of fasciculin is similar to those of the short alpha-neurotoxins and cardiotoxins, with a dense core rich in disulfide bridges and three long loops disposed as the central fingers of a hand. A comparison of these three prototypic toxin types shows that fasciculin 1 has structural features that are intermediate between those of the other two molecules. Its core region, which can be defined as a continuous stretch of conserved residues, is very similar to that of erabutoxin b, whereas the orientation of its long loops resembles that of cardiotoxin VII4. This result introduces a new element in the study of phylogenetic relationships of snake toxins and suggests that, after divergency from an ancestral gene, convergent evolution may have played an important factor in the evolution of these proteins. In fasciculin 1, several arginine and lysine residues are well ordered and relatively exposed to the solvent medium and may play a role in the binding to the peripheral site of acetylcholinesterases.
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PMID:1.9-A resolution structure of fasciculin 1, an anti-acetylcholinesterase toxin from green mamba snake venom. 142 64

A hypothalamic pathogenesis for the reduced GH secretion in aging has been reported for both animal and man. To further address this issue we studied in 31 elderly normal subjects (6 males and 25 females, aged 66-90 yr) and in 22 young healthy controls (13 males and 9 females, aged 20-35 yr) the GH responses to GHRH test (GHRH29, 1 microgram/kg i.v. as a bolus at 0 min) alone and combined with pyridostigmine, a cholinesterase inhibitor (PD, 120 mg po 60 min before GHRH), or with arginine (ARG, 30 g in 100 ml infused from 0 to 30 min). Serum IGF-I levels were lower in elderly than in young subjects (mean +/- SE: 86.9 +/- 7.2 vs 288.7 +/- 22.1 micrograms/L, p < 0.01). The GHRH-induced GH increase was lower in elderly than in young subjects (p < 0.01). PD increased the GH response to GHRH in both groups (p < 0.001), but in elderly subjects this response persisted lower (p < 0.0001) than that observed in young adults. Also ARG coadministration potentiated the GHRH-induced GH release in both groups (p < 0.0001) but in this case the elderly's responses overlapped with the young's. The GH increase observed after combined administration of ARG and GHRH was higher (p < 0.0001) than that elicited by PD plus GHRH in elderly but not in young subjects. Analyzing individual GH responses, a GH peak below the limit of normality for young adults was observed in 19 (61.3%) elderly subjects after PD plus GHRH administration while ARG plus GHRH test elicited a normal GH peak in all but one.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:A neuroendocrinological approach to evidence an impairment of central cholinergic function in aging. 147 49

Two different gene mutations associated with the silent phenotype for human serum cholinesterase were demonstrated. DNA from five individuals with silent gene phenotype of three unrelated Japanese families was amplified by the polymerase chain reaction (PCR) and analyzed by direct sequencing. The first instance demonstrated a G----C transversion at codon 365 from GGA (Gly) to CGA (Arg), which was seen in three individuals of the two families. This mutation was resulted to create a new Taq 1 restriction site (TCGA). The second mutation was shown by a double heterozygous condition with two different silent gene mutations in two members of remaining one family. These mutations were as follows: 1) one type was a frameshift mutation, in which an extra A was inserted in codon 315 (ACC----AACC) to create a new stop codon at position 322 and 2) the other was the same point mutation at codon 365 as seen in the first instance. These results indicated that many silent variants can be distinguished by direct sequence analyses of genomic DNA.
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PMID:[Identification of two different genetic mutation associated with silent phenotypes for human serum cholinesterase in Japanese]. 150 80

1. The biological properties of nine venom samples from six taxa of Micrurus were investigated. The venoms exhibited low protease, phosphodiesterase and 5'-nucleotidase activities, moderate to strong phospholipase A and hyaluronidase activities, variable L-amino acid oxidase activity and were devoid of arginine ester hydrolase and thrombin-like activities. Some venom samples exhibited strong acetylcholinesterase activity. Venoms of M. c. dumerili and M. frontalis exhibited exceptionally high alkaline phosphomonoesterase activity while two of the M. f. fulvius venom samples tested exhibited strong hemorrhagic activity in mice. 2. The polyacrylamide gel electrophoretic patterns of the venoms indicate that most of the Micrurus venom proteins are basic proteins. All Micrurus venoms tested exhibited similar SDS-polyacrylamide gel electrophoretic patterns, with an intense low mol. wt protein band. 3. The Micrurus venoms appear to exhibit biological properties similar to other elapid venoms found in Asia and Africa. There are, however, no common characteristics in the biological properties of the venoms examined at the generic level.
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PMID:The biological properties of venoms of some American coral snakes (Genus micrurus). 158 85

A 64-year-old man was admitted to our hospital because of possible liver cirrhosis. His serum cholinesterase was anomalously low with a delta pH of 0.1 (normal range; 0.8-1.1). His enzyme was more heat-labile than the normal controls. Km value of his enzyme for benzoylcholine was 1.1 x 10(-5) mol/l, while that for normal controls was 2.3 x 10(-6) mol/l. In addition, isozymic alteration of his enzyme was observed. Sequencing of the white blood cell DNA of the patient showed a point mutation at nucleotide 1093 (GGA to CGA), which changes codon 365 from glycine to arginine.
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PMID:A variant serum cholinesterase and a confirmed point mutation at Gly-365 to Arg found in a patient with liver cirrhosis. 161 Nov 88

1. The biological properties of twelve samples of venoms from all four species of Dendroaspis (mamba) were investigated. 2. Dendroaspis venoms generally exhibited very low levels of protease, phosphodiesterase and alkaline phosphomonoesterase; low to moderately low level of 5'-nucleotidase and very high hyaluronidase activities, but were devoid of L-amino acid oxidase, phospholipase A, acetylcholinesterase and arginine ester hydrolase activities. The unusual feature in venom enzyme content can be used to distinguish Dendroaspis venoms from other snake venoms. 3. All Dendroaspis venoms did not exhibit hemorrhagic or procoagulant activity. Some Dendroaspis venoms, however, exhibited strong anticoagulant activity. The intravenous median lethal dose of the venoms ranged from 0.5 microgram/g mouse to 4.2 micrograms/g mouse. 4. Venom biological activities are not very useful for the differentiation of the Dendroaspis species. The four Dendroaspis venoms, however, can be differentiated by their venom SDS-polyacrylamide gel electrophoretic patterns.
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PMID:A comparative study of the biological properties of Dendroaspis (mamba) snake venoms. 168 21

1. The protease, phosphodiesterase, alkaline phosphomonoesterase, L-amino acid oxidase, acetylcholinesterase, phospholipase A, 5'-nucleotidase, hyaluronidase, arginine ester hydrolase, procoagulant, anticoagulant and hemorrhagic activities of ten samples of venoms from seven taxa of sea snakes were examined. 2. The results show that venoms of sea snakes of both subfamilies of Hydrophiinae and Laticaudinae are characterized by a very low level of enzymatic activities, except phospholipase A activity and, for some species, hyaluronidase activity. 3. Because of the low levels of enzymatic activities and the total lack of procoagulant and hemorrhagic activities, venom biological properties are not useful for the differentiation of species of sea snakes. Nevertheless, the unusually low levels of enzymatic activities of sea snake venoms may be used to distinguish sea snake venoms from other elapid or viperid venoms.
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PMID:A comparative study of the biological properties of some sea snake venoms. 176 14


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