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:3.5.1.4 (deaminase)
5,113 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The 16S and 8S forms of acetylcholinesterase (AchE), which are composed of an elongated tail structure in addition to the more globular catalytic subunits, were extracted and purified from membranes from Torpedo californica electric organs. Their subunit compositions and quaternary structures were compared with 11S lytic enzyme which is derived from collagenase or trypsin treatment of the membranes and devoid of the tail unit. Upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis in the absence of reducing agent, appreciable populations of monomeric through tetrameric species are observed for the 11S form. Under the same conditions, the 16S form yields only monomer and dimer in addition to a higher molecular weight species. If complete reduction is effected, only the 80,000 molecular weight monomer is dominant for both the 11S and 16S forms. Cross-linking of the 11S form by dimethyl suberimidate followed by reduction yields monomer through tetramer in descending frequency, while the 16S form again shows a high molecular weight species. A comparison of the composition of the 11S and 16S forms reveals that the latter has an increased glycine content, and 1.1 and 0.3 mol % hydroxyproline and hydroxylysine, respectively. Collagenases that have been purified to homogencity and are devoid of amidase and caseinolytic activity, but active against native collagen, will convert 16S acetylcholinesterase to the 11S form. Thus, composition and substrate behavior of the 16S enzyme are indicative of the tail unit containing a collagen-like sequence. A membrane fraction enriched in acetylcholinesterase and components of basement membrane can be separated from the major portion of the membrane protein. The 16S but not the 11S form reassociates selectively with this membrane fraction. These findings reveal distinct similarities between the tail unit of acetylcholinesterase and basement membrane components and suggest a primary association of AchE with the basement membrane.
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PMID:Molecular forms of acetylcholinesterase from Torpedo californica: their relationship to synaptic membranes. 17 42

In this paper we report that acetylcholinesterase catalyzes hydrolysis of amides, an observation which had not been made previously. The amide used is an analog of acetylcholine, 2-acetoaminoethyltrimethylammonium iodide. The experiments were performed with an enzyme preparation obtained from electroplax of Electrophorus electricus. Inhibition of the enzyme by a specific organic phosphate inhibitor abolished both the esterase and the amidase activity of the enzyme. The effect of hydrogen ions between pH 5 and pH 10 on the steady-state kinetic parameters, Km and kcat, has been investigated. These parameters show essentially the same dependence on pH as is observed in catalytic hydrolysis of acetylcholine. k-cat is controlled by an ionizing group of the enzyme with an apparent pK of approximately 6.3, and reaches a pH-independent maximum value of 3.6 sec- minus 1 above pH 8. The value for Km of 1 mM at pH 7 and 25 degrees is about five times greater than that for catalytic hydrolysis of the ester at the same pH and temperature. Preliminary electrophysiological experiments indicate that the amide analog binds to the receptor less well, by several orders of magnitude, than acetylcholine does.
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PMID:Acetylcholinesterase-catalyzed hydrolysis of an amide. 116 63

Acetylcholinesterase (EC 3.1.1.7) and butyrylcholinesterase (EC 3.1.1.8) in human amniotic fluid were estimated in the presence of selective inhibitors. Amniotic fluid cholinesterases (mixture of acetylcholinesterase and butyrylcholinesterase) purified by procainamide-Sepharose affinity chromatography exhibited aryl acylamidase activity which was sensitive to serotonin inhibition (a property of aryl acylamidases associated with both acetyl- and butyrylcholinesterases) and tyramine activation (shown exclusively by aryl acylamidase associated with butyrylcholinesterase). Tyramine activation was unaffected in the presence of the selective acetylcholinesterase inhibitor BW284C51 whereas it was abolished in the presence of the selective butyrylcholinesterase inhibitor ethopropazine, suggesting the presence of both types of aryl acylamidases in amniotic fluid, one associated with acetylcholinesterase and the other associated with butyrylcholinesterase. Butyrylcholinesterase and the associated aryl acylamidase activity in the affinity purified enzyme was selectively immunoprecipitated by a polyclonal antibody raised against human serum butyrylcholinesterase. Estimation of the activity ratio of acetylcholinesterase to butyrylcholinesterase in a few samples of amniotic fluid showed that this could vary depending on the butyrylcholinesterase arising from contaminating blood in the samples. Gel electrophoresis under non-denaturing conditions and enzyme staining showed that butyrylcholinesterase band was detectable on the gel in all the samples whereas acetylcholinesterase band was below detectable levels in normal samples but visible in samples from pregnancies of neural tube defect fetuses. It is suggested that the use of selective cholinesterase inhibitors along with gel electrophoresis and immunoprecipitation studies may be useful in the assessment of cholinesterase activities in human amniotic fluid.
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PMID:Cholinesterases exhibiting aryl acylamidase activity in human amniotic fluid. 134 16

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

Purified human serum butyrylcholinesterase (approximately 90-kDa subunit) is known to exhibit aryl acylamidase and peptidase activity. Limited alpha-chymotrypsin digestion of the purified butyrylcholinesterase gave three major protein fragments of approximately 50 kDa, approximately 21 kDa and approximately 20 kDa. In our earlier studies [Rao and Balasubramanian (1989) Eur. J. Biochem. 179, 639-644] we characterized the approximately 20-kDa fragment and showed that it exhibited both butyrylcholinesterase and aryl acylamidase activities. In the present studies the approximately 50-kDa fragment is characterized. This fragment, after isolation by Sephadex G-75 chromatography from a chymotryptic digest of purified butyrylcholinesterase, exhibited only peptidase activity and was devoid of cholinesterase and aryl acylamidase activities. It could bind to a column of Ricinus communis agglutinin bound to Sepharose, indicating its glycosylated nature and the presence of galactose. The peptidase activity in the approximately 50-kDa fragment could be immuno-precipitated by a polyclonal antibody raised against purified butyrylcholinesterase. SDS-gel electrophoresis of this fragment isolated by R. communis agglutinin-Sepharose and Sephadex G-75 chromatography showed a protein band of approximately 50 kDa by silver staining. Amino-terminal sequence analysis of the approximately 50-kDa fragment gave the sequence of Gly-Pro-Thr-Val-Asp which corresponded to amino acid residues 291-295 in the butyrylcholinesterase sequence [Lockridge et al. (1987) J. Biol. Chem. 262, 549-557]. The combined results suggested that alpha-chymotrypsin digestion of human serum butyrylcholinesterase resulted in the formation of a approximately 20-kDa fragment exhibiting both cholinesterase and aryl acylamidase activities and a approximately 50-kDa fragment exhibiting only peptidase activity.
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PMID:Localization of the peptidase activity of human serum butyrylcholinesterase in a approximately 50-kDa fragment obtained by limited alpha-chymotrypsin digestion. 233 89

Purified human serum butyrylcholine esterase (approximately 90-kDa subunit), which also exhibits aryl acylamidase activity, was subjected to limited alpha-chymotrypsin digestion. Three major protein fragments of approximately 50 kDa, approximately 21 kDa and approximately 20 kDa were found to be produced, as observed by SDS-gel electrophoresis of the chymotryptic digest. The purified butyrylcholine esterase could fully bind to a Ricinus-communis-agglutinin-Sepharose column but after chymotryptic digestion about 15-20% of the enzyme activity remained unbound and was recovered in the run-through fractions. Sephadex G-75 chromatography of the chymotryptic digest showed an enzymatically active fragment eluted at an approximate molecular mass of 20 kDa, apart from the undigested butyrylcholine esterase eluted at the void volume. The butyrylcholine esterase fragment that did not bind to Ricinus communis agglutinin also was eluted at an approximate molecular mass of 20 kDa from a Sephadex G-75 column. This enzymatically active low-molecular-mass fragment from Sephadex G-75 chromatography showed a single protein band of approximately 20 kDa on SDS-gel electrophoresis. Neutral sugar analysis of the approximately 20 kDa fragment showed the presence of mannose only, whereas the undigested butyrylcholine esterase showed the presence of both mannose and galactose. Amino-terminal-sequence analysis of the approximately 20 kDa fragment showed the sequence Arg-Val-Gly-Ala-Leu, which agrees with amino acid residues 147-151 reported for human serum butyrylcholine esterase [Lockridge et al. (1987) J. Biol. Chem. 262, 549-557]. Both cholinesterase and aryl acylamidase activities were co-eluted in all chromatographic procedures. The results suggested that limited alpha-chymotrypsin digestion of human serum butyrylcholine esterase resulted in the formation of a approximately 20-kDa enzymatically active fragment with Arg147 as its N-terminal residue and which was devoid of galactose.
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PMID:Isolation of a galactose-free 20-kDa fragment exhibiting butyrylcholine esterase and aryl acylamidase activity from human serum butyrylcholine esterase by limited alpha-chymotrypsin digestion. 264 20

Human cerebrospinal fluid contained both acetylcholinesterase (EC 3.1.1.7) and butyrylcholinesterase (EC 3.1.1.8) and they were estimated in the presence of selective inhibitors. Butyrylcholinesterase of human cerebrospinal fluid was similar to human serum butyrylcholinesterase in its electrophoretic mobility, glycoprotein nature and tyramine activation of the aryl acylamidase (EC 3.5.1.13) activity exhibited by butyrylcholinesterase. Moreover antibody raised against human serum purified butyrylcholinesterase could completely immunoprecipitate butyrylcholinesterase from human cerebrospinal fluid without affecting acetylcholinesterase. It is suggested that a useful method for the precise determination of acetylcholinesterase in human cerebrospinal fluid would be removal of butyrylcholinesterase by immunoprecipitation using antibody raised against human serum butyrylcholinesterase.
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PMID:Human cerebrospinal fluid acetylcholinesterase and butyrylcholinesterase. Evidence for identity between the serum and cerebrospinal fluid butyrylcholinesterase. 279 3

The toxic and biological activities of four samples of Trimeresurus purpureomaculatus venom were examined. The lethality, protein composition and biological activities of the four venom samples were similar. Three of the venom samples had LD50 (i.v.) values of 0.9 micrograms/g while the fourth had a lower LD50 (i.v.) of 0.45 micrograms/g. All four venom samples exhibited hemorrhagic, edema-inducing, anticoagulant and thrombin-like activities as well as the usual enzymes found in crotalid venoms. DEAE-Sephacel ion exchange chromatographic fractionation of the venom yielded 10 protein fractions. Only two fractions (fractions A and F) were lethal to mice; the major lethal fraction being fraction F. This fraction had an LD50 (i.v.) of 0.2 micrograms/g and exhibited hemorrhagic, edema-inducing and thrombin-like activity. It also exhibited phospholipase A, arginine ester hydrolase, arginine amidase, protease, 5'-nucleotidase, acetylcholinesterase and alkaline phosphomonoesterase activities. The lethal potency of fraction F is potentiated by fraction G, which exhibited anticoagulant activity as well as hemorrhagic, edema-inducing and enzymatic activities. Fractions F plus G account for almost 100% of the lethal potency of the venom.
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PMID:Biological properties of Trimeresurus purpureomaculatus (shore pit viper) venom and its fractions. 324 58

Phosphatidylinositol specific phospholipase C from Staphylococcus aureus could solubilize acetylcholinesterase up to 55% from sheep platelets in the presence of ethylenediaminetetra acetic acid (EDTA). The endogenous phosphatidylinositol specific phospholipase C of platelets activated by deoxycholate (at 3-5 mM) could also solubilize the enzyme to a similar extent. The solubilized enzyme could be further purified to apparent homogeneity by affinity chromatography without the use of any detergents. It is suggested that phosphatidylinositol specific phospholipase C will be a useful tool in the solubilization of acetylcholinesterase from mammalian sources and its purification free of detergents. The present study also demonstrates the parallel behaviour of acetylcholinesterase and aryl acylamidase in platelets confirming their identity.
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PMID:The solubilization of platelet membrane-bound acetylcholinesterase and aryl acylamidase by exogenous or endogenous phosphatidylinositol specific phospholipase C. 393 20

Erythrocyte acetylcholinesterase (EC 3.1.1.7) and plasma pseudocholinesterase (EC 3.1.1.8) were determined from the day of admission up to 10 days in patients who have consumed organophosphate or carbamate poisons. In a number of patients, plasma pseudocholinesterase was completely inhibited on the day of admission but increased with the passage of days. Erythrocyte acetylcholinesterase was not completely inhibited and it also tended to increase with time in most cases. Patients in whom the erythrocyte acetylcholinesterase was very low and did not show an increase within the first few days expired indicating the prognostic importance of erythrocyte acetylcholinesterase. The profile of aryl acylamidase (EC 3.5.1.13) activity in plasma or erythrocytes showed a pattern similar to the respective cholinesterases. Moreover, whole blood aryl acylamidase activity was found to be a good index of erythrocyte acetylcholinesterase suggesting the prognostic usefulness of blood aryl acylamidase in the poisoned patients.
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PMID:Aryl acylamidase activity in human erythrocyte, plasma and blood in pesticide (organophosphates and carbamates) poisoning. 397 15


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