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)

Purified human erythrocyte acetylcholinesterase was labeled by reductive radiomethylation with saturating amounts of [14C]formaldehyde and sodium cyanoborohydride. Acid hydrolysis and automated amino acid analysis permitted both identification of radiomethylated components by their coelution with radiomethylated standards and quantitation of these components. The methylated N-terminal amino acids glutamate and arginine were observed at levels of 0.66 and 0.34 residues, respectively, per 70-kilodalton subunit, and lysine residues were methylated on their epsilon-amino groups to a level of 7.40 residues per subunit [Haas, R., & Rosenberry, T.L. (1985) Anal. Biochem. 148, 154-162]. In addition, each subunit contained 1.35 residues of methylated ethanolamine and 0.98 residue of methylated glucosamine. Papain digestion cleaved the intact enzyme into two fragments, an enzymatically active hydrophilic fragment and a small hydrophobic fragment that represented the membrane-binding domain. The radiomethylated amino acids were quantitatively retained in the hydrophilic fragment, while the methylated ethanolamine and glucosamine were confined exclusively to the hydrophobic domain fragment. This fragment included the C-terminal dipeptide of the subunit. Peptide sequencing by manual Edman methods was combined with radiomethylation to demonstrate the sequence His-Gly-ethanolamine-Z for the hydrophobic domain fragment. The ethanolamine residue in this sequence is in amide linkage to the C-terminal Gly and is clearly distinct from the ethanolamine residues in Z which are susceptible to radiomethylation in the intact enzyme. Since Z also includes glucosamine and 2 mol of fatty acids [Roberts, W.L. & Rosenberry, T.L. (1985) Biochem. Biophys. Res. Commun. 133, 621-627], we conclude that the membrane-binding domain of human erythrocyte acetylcholinesterase is a covalently linked glycolipid at the C-termini of the subunits.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:Identification of amine components in a glycolipid membrane-binding domain at the C-terminus of human erythrocyte acetylcholinesterase. 352 71

Active-site tryptic peptides were isolated from three genetic types of human serum cholinesterase. The active-site peptide was identified by labeling the active-site serine with [3H]diisopropylfluorophosphate. Peptides were purified by high-performance liquid chromatography. Amino acid composition and sequence analysis showed that the peptide from the usual genotype contained 29 residues with the sequence Ser-Val-Thr-Leu-Phe-Gly-Glu-Ser-Ala-Gly-Ala-Ala-Ser-Val-Ser-Leu-His-Leu- Leu-Ser-Pro-Gly-Ser-His-Ser-Leu-Phe-Thr-Arg. The active-site serine was the eighth residue from the N-terminal. The peptide containing the active-site serine from the atypical genotype contained 22 residues with the sequence Ser-Val-Thr-Leu-Phe-Gly-Glu-Ser-Ala-Gly-Ala-Ala-Ser-Val-Ser-Leu-His-Leu- Leu-Ser-Pro-Gly. The peptide from the atypical-silent genotype contained eight residues with the sequence Gly-Glu-Ser-Ala-Gly-Ala-Ala-Ser. Thus, the sequences of the atypical and atypical-silent active-site peptides were identical to the corresponding portions of the usual peptide.
...
PMID:Amino acid sequence of the active site of human serum cholinesterase from usual, atypical, and atypical-silent genotypes. 374 70

The impact of maternal starvation in late gestation on development of some enzymatic mechanisms concerned with neurotransmission and polyamine synthesis was studied in fetal rat brain. Between 17 and 20 d, acetylcholinesterase and choline acetyltransferase activity increased in fetal brains of fed dams, whereas maternal starvation from day 17 to day 20 resulted in heightened acetylcholinesterase but not choline acetyltransferase activity. Ornithine decarboxylase activity on a per-gram wet-weight basis fell between 17 and 20 d in fetal brain from fed dams. Increasing the duration of maternal starvation resulted in a progressive increase in fetal brain ornithine decarboxylase. Arginine and putrescine levels in the brain were lower in fetuses of starved mothers while spermidine and spermine concentrations were unchanged. Since the Km of ornithine decarboxylase for ornithine was found to vary directly with levels of putrescine in fetal brain, lower concentrations of putrescine and greater ornithine decarboxylase activity in fetal brains from starved mothers suggested that levels of this enzyme may be controlled in part by putrescine. Changes in the maternal nutritional state had no effect on the activity of glutamate decarboxylase in fetal brain, and tissue levels of the product, gamma-aminobutyric acid, were unchanged. Thus changes in ornithine decarboxylase and acetylcholinesterase activity in fetal brain may uniquely reflect biochemical alterations consequent to maternal starvation.
...
PMID:Enzyme markers of maternal malnutrition in fetal rat brain. 381 61

A novel method of determining N-terminal amino acids in proteins is introduced. Reductive methylation of a protein with radiolabeled formaldehyde methylates both the alpha-amino group of the N-terminal amino acid and the epsilon-amino groups of Lys residues. The radiomethylated amino acids are stable to acid hydrolysis, and each of 16 possible hydrolysis-stable N-terminal amino acids can be identified by the unique elution positions of its N alpha-methyl and N alpha,N alpha-dimethyl derivatives with an appropriate amino acid analyzer elution schedule. The technique is at least as sensitive as other N-terminal amino acid determinations and, in addition, permits a quantitative evaluation of the number of N-terminal groups in a sample. Reductive methylation of bovine serum albumin revealed N-terminal Asp at a stoichiometry of 0.97 amino acid residue per polypeptide, while methylation of prolactin resulted in 0.86 residue of N-terminal Thr per polypeptide. Human erythrocyte acetylcholinesterase contained two N-terminal amino acids with stoichiometries of 0.66 Glu and 0.34 Arg per 70-kDa subunit. Identification of Glu as the principal N-terminus of acetylcholinesterase was confirmed by Edman sequencing.
...
PMID:Quantitative identification of N-terminal amino acids in proteins by radiolabeled reductive methylation and amino acid analysis: application to human erythrocyte acetylcholinesterase. 403 98

p-(Amidinophenyl)methanesulfonyl fluoride (p-APMSF) has been synthesized and shown to be a specific, irreversible inhibitor of the class of plasma serine proteases which demonstrate substrate specificity for the positively charged side chains of the amino acid lysine or arginine. In equimolar concentration, this compound causes immediate and complete irreversible inhibition of bovine trypsin and human thrombin. A 5-10-fold molar excess of reagent over enzyme is required to achieve complete irreversible inhibition of bovine Factor Xa, human plasmin, human C1-r, and human C1-s. the Ki of p-APMSF for all of the above-mentioned proteases is between 1 and 2 microM. In contrast, p-APMSF in large molar excess does not inactivate chymotrypsin or acetylcholinesterase. The unique reactivity of p-APMSF has been further shown in comparison with the related compound p-nitrophenyl (p-amidinophenyl)methanesulfonate which is an active-site titrant for thrombin but reacts poorly with Factor Xa, C1-r, and C1-s and is not hydrolyzed by bovine trypsin or human plasmin. Similarly, (p-amidinophenyl)methanesulfonate has a Ki of 30 microM for thrombin but is a poor inhibitor of trypsin, Factor Xa, C1-r, C1-s, and plasmin. Studies with bovine trypsin have demonstrated that the inhibitory activity of p-APMSF is the result of its interaction with the diisopropyl fluorophosphate reactive site. The unique reactivity of this inhibitor classifies it as one of the most effective active site directed reagents for this class of serine proteases. Collectively, these results suggest that the primary substrate binding site of these enzymes, which share a high degree of structural homology, do in fact significantly differ from each other in their ability to interact with low molecular weight inhibitors and synthetic substrates.
...
PMID:(p-Amidinophenyl)methanesulfonyl fluoride, an irreversible inhibitor of serine proteases. 677 96

A protein isolated from sciatic nerves of adult chickens promotes the morphological maturation and maintenance of embryonic avian skeletal muscle cells in the absence of innervation and is required for normal myogenesis in vitro. This trophic protein, sciatin, has been purified by ion exchange column chromatography on DEAE-cellulose followed by gel filtration on Sephadex G-100. Sciatin migrated as a single polypeptide chain of molecular weight 84,000 on sodium dodecyl sulfategel electrophoresis. The native molecular weight of sciatin as determined by sedimentation equilibrium centrifugation was 86,400. Amino acid analysis revealed that sciatin is relatively deficient in tryptophan, histidine, glycine, and arginine, but enriched in cysteine, methionine, alanine, and lysine. Carbohydrate determination showed that sciatin in composed of 11% sugar by weight with no detectable N-acetylneuraminic acid residues. Sedimentation velocity centrifugation studies revealed an S20,w0 of 5.11 with a frictional coefficient of 1.31. Sciatin had no detectable protease or acetylcholinesterase activity. The results of the present study provide new biochemical information on a macromolecule with biological activities similar to those expressed by the "maintenance" group of growth factors which includes such proteins as nerve growth factor.
...
PMID:Sciatin: purification and characterization of a myotrophic protein from chicken sciatic nerves. 699 6

Neurons containing reduced nicotinamide adenine dinucleotide phosphate (NADPH) diaphorase and acetylcholinesterase in the striatum are spared in Huntington's disease. It has been claimed that these neurons are also spared after intrastriatal injection of the N-methyl-D-aspartate receptor agonist, quinolinic acid. In the present study the effects of intrastriatal injection of quinolinic acid (15, 30 and 60 nmol) on neurons containing NADPH diaphorase and acetylcholinesterase were examined in rats. Neurons identified histochemically were counted in whole striatal sections at the level of the injection site and at 400 microns intervals anterior and posterior to the injection site. There was a dose-related reduction in the total number of NADPH diaphorase-containing neurons counted in these levels, but only a mild loss of acetylcholinesterase-containing neurons. Acetylcholinesterase-positive neurons were observed near the injection site following administration of all doses. The effects of the nitric oxide synthase inhibitor, NG-nitro-L-arginine methyl ester (50 mg/kg, i.p. twice daily for seven days), on quinolinic acid (30 nmol. day 5)-induced toxicity were also investigated. Striatal sections were stained for NADPH diaphorase-, nitric oxide synthase- and acetylcholinesterase-containing neurons and cells were counted in whole striatal sections at the level of the injection site and at four levels posterior to the injection site. Nitric oxide synthase activity was measured in striatal homogenates. NG-Nitro-L-arginine methyl ester did not protect against or potentiate the loss of NADPH diaphorase-, nitric oxide synthase- or acetylcholinesterase-containing neurons or the loss in nitric oxide synthase activity. Acute intrastriatal injection of quinolinic acid may not be a suitable model for Huntington's disease and a role for nitric oxide in quinolinic acid-induced toxicity is not supported in this model.
...
PMID:The effect of nitric oxide synthase inhibition on quinolinic acid toxicity in the rat striatum. 754 92

The fasciculins are a family of closely related peptides that are isolated from the venom of mambas and exert their toxic action by inhibiting acetylcholinesterase (AChE). Fasciculins belong to the structural family of three-fingered toxins from Elapidae snake venoms, which include the alpha-neurotoxins that block the nicotinic acetylcholine receptor and the cardiotoxins that interact with cell membranes. The features unique to the known primary and tertiary structures of the fasciculin molecule were analyzed. Loop I contains an arginine at position 11, which is found only in the fasciculins and could form a pivotal anchoring point to AChE. Loop II contains five cationic residues near its tip, which are partly charge-compensated by anionic side chains in loop III. By contrast, the other three-fingered toxins show full charge compensation within loop II. The interaction of fasciculin with the recognition site on acetylcholinesterase was investigated by estimating a precollision orientation followed by determination of the buried surface area of the most probable complexes formed, the electrostatic field contours, and the detailed topography of the interaction surface. This approach has led to testable models for the orientation and site of bound fasciculin.
...
PMID:Theoretical analysis of the structure of the peptide fasciculin and its docking to acetylcholinesterase. 761 68

1. NG-monomethyl-L-arginine (L-NMMA, a nitric oxide synthase inhibitor) inhibits vasodilator responses to acetylcholine but not methacholine in human forearm vasculature. To investigate whether this difference results from the relative susceptibility of these agonists to hydrolysis by acetylcholinesterase, we studied vasodilator responses to brachial artery administration of acetylcholine alone and in the presence of the acetylcholinesterase inhibitor edrophonium. 2. Vasodilator responses to constant-rate brachial artery infusions of acetylcholine were biphasic, with an initial peak response fading over 2 min to a plateau. Fade [(peak-plateau)/peak x 100%] was dose dependent (P < 0.02), ranging from 43 +/- 7% (mean +/- SEM) at low dose (16 nmol/min) to 9 +/- 8% at high dose (83 nmol/min). 3. Edrophonium (0.5 mumol/min intra-arterially) alone produced no change in forearm blood flow but increased blood flow responses to acetylcholine (P < 0.01), causing an approximately 10-fold reduction in the dose required to increase plateau blood flow by 10 ml min-1 100 ml-1. 4. Responses to low doses of acetylcholine alone (16 and 41 nmol/min) faded more (P < 0.01) than those to doses of acetylcholine with edrophonium chosen to produce similar plateau blood flows. Responses to acetylcholine (41 nmol/min) also faded more (P < 0.01) than those to methacholine (5 nmol/min), producing matched plateau flows. 5. Peak and plateau responses to acetylcholine (41 nmol/min) were reduced (P < 0.01) by similar amounts (47 +/- 15%, and 37 +/- 13% respectively, P = 0.39) by coinfusion of L/NMMA (4 mumol/min).(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:Inhibition of acetylcholinesterase selectively potentiates NG-monomethyl-L-arginine-resistant actions of acetylcholine in human forearm vasculature. 770 91

The nervus terminalis is a ganglionated vertebrate cranial nerve of unknown function that connects the brain and the peripheral nasal structures. To investigate its function, we have studied nervus terminalis ganglion morphology and physiology in the bonnethead shark (Sphyrna tiburo), where the nerve is particularly prominent. Immunocytochemistry for gonadotropin-releasing hormone (GnRH) and Leu-Pro-Leu-Arg-Phe-NH2 (LPLRFamide) revealed two distinct populations of cells. Both were acetylcholinesterase positive, but LPLR-Famide-immunoreactive cells consistently stained more darkly for acetylcholinesterase activity. Tyrosine hydroxylase immunocytochemistry revealed fibers and terminal-like puncta in the ganglion, primarily in areas containing GnRH-immunoreactive cells. Consistent with the anatomy, in vitro electrophysiological recordings provided evidence for cholinergic and catecholaminergic actions. In extracellular recordings, acetylcholine had a variable effect on baseline ganglion cell activity, whereas norepinephrine consistently reduced activity. Electrical stimulation of the nerve trunks suppressed ganglion activity, as did impulses from the brain in vivo. During electrical suppression, acetylcholine consistently increased activity, and norepinephrine decreased activity. Muscarinic and, to a lesser extent, alpha-adrenergic antagonists both increased activity during the electrical suppression, suggesting involvement of both systems. Intracellular recordings revealed two types of ganglion cells that were distinguishable pharmacologically and physiologically. Some cells were hyperpolarized by cholinergic agonists and unaffected by norepinephrine; these cells did not depolarize with peripheral nerve trunk stimulation. Another group of cells did depolarize with peripheral trunk stimulation; a representative of this group was depolarized by carbachol and hyperpolarized by norepinephrine. These and other data suggest that the bonnethead nervus terminalis ganglion contains at least two cell populations that respond differently to acetylcholine and norepinephrine. The bonnethead nervus terminalis ganglion appears to differ fundamentally from sensory and autonomic ganglia but does share some features with the neural circuits of forebrain GnRH systems.
...
PMID:Nervus terminalis ganglion of the bonnethead shark (Sphyrna tiburo): evidence for cholinergic and catecholaminergic influence on two cell types distinguished by peptide immunocytochemistry. 770 49


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

---