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

---

Query: EC:3.1.1.7 (acetylcholinesterase)
28,390 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Muscle acetylcholinesterase (AChE) in unregulated in animal and human muscular dystrophies and its activity is elevated in plasma of dystrophic chickens, probably due to a leakage from affected muscles. It is possible to measure AChE activity in human plasma in spite of high butyrylcholinesterase activity if acetyl-beta-methylcholine is used as the substrate and butyrylcholinesterase is inhibited by iso-OMPA. It has been found that, unlike in chickens, the plasma AChE activity in human newborns is not higher than that in adults. The AChE activity in plasma of children afflicted by Duchenne muscular dystrophy does not differ from that found in plasma of normal boys of the same age. In this respect Duchenne muscular dystrophy differs from chicken muscular dystrophy as well as from a neurogenic muscle disease (amyotrophic lateral sclerosis) in man.
...
PMID:Plasma acetylcholinesterase in Duchenne muscular dystrophy. 684 Feb 42

Rat obturator nerve 16S acetylcholinesterase (16S AChE) was separated by sucrose gradient velocity sedimentation and compared to the 16S form of AChE similarly derived from endplate regions of anterior gracilis muscles. The 16S AChE from both tissues could only be extracted in high ionic strength buffer; as it aggregated under low ionic strength conditions. Treatment of nerve and muscle 16S AChE with purified collagenase, in the presence of calcium, caused an identical "shift" in the enzyme's sedimentation coefficient to 17.5S. Other properties which were also equivalent for 16S AChE from both tissue sources included: an excess substrate inhibition above 2 x 10(-3) M acetylcholine and Km of 1.6 x 10(-4) M, relative sensitivity to the specific inhibitors BW284C51 (I50 of 5 x 10(-8) M) and Iso-OMPA (I50 of 5 x 10(-4) M), and a half maximal thermal inactivation at 62.5 degrees C. These and additional results indicate that the 16S forms of AChE in both tissues are analogous molecules, which have a highly asymmetric conformation probably containing a collagen-like domain. The present findings are also consistent with the view that motor neurons provide at least a fraction of the 16S AChE present at the neuromuscular junction.
...
PMID:Properties of 16S acetylcholinesterase from rat motor nerve skeletal muscle. 732 60

The rates of regeneration of acetylcholinesterase (AChE) and propionylcholinesterase (PrChE) in the supernatants of aqueous homogenates of rat superior cervical ganglia, centrifuged at 100,000 g for 90 min, were determined at 1, 3, 6, and 16 h following their inactivation (greater than 90%) by administration of sarin, 2.0 mumol/kg i.v. Values were compared with those in animals in which the PrChE was continually suppressed by the repeated, fractional administration of iso-OMPA, in a total dose of 10 or 20 mumol/kg i.p. These doses of iso-OMPA alone produced 96-99% inactivation of PrChE with no detectable effect on AChE. Significant suppression of AChE regeneration by iso-OMPA administration was noted only at 6 h; in contrast with earlier findings in the cat, administration of iso-OMPA alone caused no significant increase in ganglionic AChE activity.
...
PMID:Effects of selective alkylphosphorylation of propionylcholinesterase on the regeneration of acetylcholinesterase in the aqueous soluble fraction of superior cervical ganglia of the rat following sarin. 746 67

Serum pseudocholinesterase (PChE) was discovered in 1932. Since this protein mimics many of the catalytic properties of acetylcholinesterase, it has traditionally been referred to as PChE, even though its true biological function is unknown. Serum PChE is synthesized in the liver and secreted into the circulation as a sialated glycoprotein. Although no convincing evidence of biological function exists, a significant number of obese and diabetic patients have elevated levels of PChE. The same phenomenon is found in experimental animal models of obesity, diabetes and hyperlipoproteinemia. Streptozotocin-induced diabetic mice showed increased serum PChE activity concomitant with increased serum triacylglycerol and PChE activity declined with treatment. Iso-OMPA, a nontoxic inhibitor of serum PChE, reduced serum and liver triacylglycerols and serum VLDL in streptozotocin-induced rodent diabetes. These findings suggest that PChE may have a role in VLDL metabolism.
...
PMID:Serum pseudocholinesterase and very-low-density lipoprotein metabolism. 793 19

During chicken neurogenesis, the sequential expression of butyrylcholinesterase (BChE) and acetylcholinesterase (AChE) between final cell proliferation and differentiation is functionally not understood. Recently, cholinesterases have been shown to regulate neurite growth in vitro. Here, we investigated the effects of inhibition of BChE on laminar histogenesis in retinospheroids that arise from dissociated embryonic chicken retinal cells in rotation culture. In the presence of the BChE inhibitor iso-OMPA (tetraisopropyl pyrophosphoramide), the number of spheroids/dish is increased, and their diameter is decreased by about 20%, corresponding to about 50% volume size. As a corollary, the course of histotypical differentiation is dramatically accelerated. Thus as a consequence of BChE inhibition both, organization of nuclear cell layers and of plexiform-like (neuropile) areas, as detected by an antibody to the fiber fasciculation protein F11, is temporally advanced by at least two days. Moreover, AChE is almost fully diminished in these areas. The results further demonstrate novel roles of cholinesterases during laminar histogenesis of coherent neural networks in vitro.
...
PMID:Butyrylcholinesterase regulates laminar retinogenesis of the chick embryo in vitro. 795 7

The occurrence of cholinesterases has been demonstrated in retinas of several mammalian species. Histochemical staining techniques indicate that the acetylcholinesterases (AChE) are present in amacrine cells and their neighboring bipolar cells. However, the nature of retinal cholinesterases and their interactions with specific cholinesterase inhibitors are not known. Therefore, we have studied the inhibition of the rat retinal cholinesterase activity by BW284C51, a selective inhibitor of AChE, and iso-OMPA, a selective inhibitor of butyrylcholinesterase (BChE). Retinas from Zivic-Miller rats were solubilized by sonication in phosphate buffer (0.134 M, pH 7.2) at 4 degrees C for 20 min. The cholinesterase activity in the sonicate was determined by a radiometric method using 14C-acetylcholine (ACh) as substrate (10(-2) M). Excess 14C-ACh was adsorbed by Amberlite CG-120 cation exchange resin. 14C-acetate formed and retained in the aqueous medium was determined by liquid scintillation counting. This study gave the following results: (a) Rat retinal sonicate gave total cholinesterase activity of 3.76 mumol of ACh hydrolyzed/mg protein/15 min; (b) This activity was inhibited by BW284C51 (IC50, 0.115 microM). Iso-OMPA (IC50, 500 microM) did not cause significant inhibition at 0.115 microM. These observations suggest that the rat retinal cholinesterase is predominantly AChE.
...
PMID:Nature of cholinesterase in the rat retina. 820 26

F. seoulensis were obtained from artificially infected albino rats at 3, 4, 5, 6, 7 days after infection. The worms and metacercariae were washed in physiological saline solution, and fixed with 10% neutral formalin. The acetylcholinesterase (AchE) stained by enzyme histochemistry using acetylthiocholine iodide as substrate. Eserine, iso-OMPA and BW284C51 were used as inhibitors of AchE. The nervous system consists of three pairs longitudinal nerve trunks interconnected with excretory plexus in posterior half, and pharynx and oral sucker in anterior half of metacercariae and adults. The longitudinal nerve trunks are interconnected with transverse commissures and numerous circular commissures. Considerable numbers of circular commissures are interconnected with longitudinal nerve trunks lying on the surface of the worms. At each stage of juvenile worms, AchE and nonspecific cholinesterase activities were observed in the oral sucker, ventral sucker, pharynx and nerve system. Isozymes of AchE in F. seoulensis were separated into the two bands, 69 kDa and 132 kDa. The major band was 69 kDa.
...
PMID:[The nervous system of Fibricola seoulensis by acetylcholinesterase histochemistry]. 829 89

Pretreatment of rats with iso-OMPA one hour prior to each of the N-methylcarbamate insecticides, carbofuran, propoxur, or aldicarb, potentiated the toxicity of these carbamates threefold. None of these compounds alone in the dosage used produced toxic signs; however, carboxylesterase (CarbE) activity in a variety of organs including brain, muscle, liver, and plasma was significantly reduced, while acetylcholinesterase (AChE) activity was unchanged. Significant inhibition of AChE was observed after the combination of tetraisopropylpyrophosphoramide (iso-OMPA) with each one of these N-methylcarbamates. It is suggested that CarbEs are more sensitive than AChE to these N-methylcarbamates and inhibition of CarbE by iso-OMPA raises the concentration of N-methylcarbamates available to inhibit AChE resulting in increased toxicity. Other N-methylcarbamates such as physostigmine do not inhibit CarbE, nor are their toxicities potentiated by iso-OMPA.
...
PMID:Role of carboxylesterases in the prevention and potentiation of N-methylcarbamate toxicity. 834 87

Cholinesterase activity is detectable in the Japanese quail embryo, in the yolk and subembryonic liquid, but not in the albumen. Obviously, this enzyme is deposited by the hen into the yolk and from there it is transferred to the subembryonic liquid. In contrast, in the embryo the enzyme is synthesized by itself and the amount increases with the age of the embryo. By using BW284c51 1,5-bis-(4-allyldimethylammoniumphenyl)pentan-3-one bromide and ISO-OMPA tetraisoprophylpyrophosphoramide as inhibitors, it was found that the enzyme in the embryo is predominantly acetylcholinesterase (EC 3.1.1.7), whereas that in the yolk and subembryonic liquid is butyrylcholinesterase (EC 3.1.1.8). Both types are inhibited by dichlorphos. However, the embryonic enzyme activity is restored within 8 hr, whereas that in the subembryonic liquid remained inactive at least for 72 hr after inhibition. Enzyme inhibition leads to retardation of the development, to reduced accumulation of glucose and amino acids in the subembryonic liquid and finally to death of the embryo, suggesting that the developmental retardation is due to the restricted supply of glucose and amino acids. Surprisingly, most of the embryos die when the embryonic enzyme activity has again been restored.
...
PMID:Activity of cholinesterases in the Japanese quail embryo. Effects of dichlorphos on the embryonic development. 842 27

The occurrence of cholinesterases (ChE) has been demonstrated in retinas of several mammalian species. Using BW284C51 and iso-OMPA as selective inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), respectively, it has been demonstrated that the rat retinal ChE is predominantly AChE. Therefore the kinetic nature of inhibition of the rat retinal AChE by BW284C51 was studied using acetyl-6-methylthiocholine (AMTCh) as a selective substrate of AChE. AChE activity of the rat retinal sonicates was assayed using AMTCh as the substrate in the presence of 5,5-dithiobis-2-nitrobenzoate and yellow 5-thio-2-nitrobenzoic anion was measured by the absorption at 412 millimicrons using a spectrophotometer. The substrate (AMTCh) was varied between 0.1 and 0.5 mM. The inhibitor concentrations used were 2.1 and 4.2 nM. Double-reciprocal plots between substrate concentrations and the velocities for the enzymatic hydrolysis of AMTCh in the presence and absence of inhibitor were constructed. This study gave the following results: BW284C51 was a potent inhibitor of the hydrolysis of AMTCh by rat retinal AChE (IC50, 5.2 nM). The nature of the inhibition was found to be competitive as the double reciprocal plots with and without the inhibitor crossed on the ordinate.
...
PMID:Evaluation of the nature of rat retinal acetylcholinesterase using a specific substrate and a specific inhibitor. 859 Feb 72


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---