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:3.1.1.5 (neuropathy target esterase)
1,070 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. The effects of six local anaesthetics have been studied on the activities of soluble phospholipases A2 (EC 3.1.1.4) and lysophospholipase (EC 3.1.1.5). 2. Phospholipase A2 activity in human seminal plasma towards sonicated radioactively-labelled phosphatidylethanolamine was slightly stimulated a low and inhibited at high concentrations of all anaesthetic compounds employed. The order of decreasing potency was chlorpromazine, dibucaine, tetracaine, lidocaine, cocaine and procaine. In line with previous findings, the mode of inhibition was seen to be competitive with respect to Ca2+. 3. Phospholipase A2 activity in crude venom of Crotalus adamanteus was not affected or slightly stimulated by local anaesthetics up to 10(-2) M concentrations, when egg yolk was used as substrate. However, with sonicated radioactively-labelled phosphatidylcholine or phosphatidylethanolamine as substrate, stimulation of phospholipase activity was seen with all local anaesthetics up to 10(-2) M, the order of decreasing potency again being chlorpromazine, dibucaine, tetracaine, lidocaine, cocaine and procaine. The mode of stimulation was seen to be un-competitive with respect to substrate and probably independent of any involvement of Ca2+. 4. As in seminal plasma phospholipase A2, the activity in crude Naja naja venom towards sonicated radioactively labelled phosphatidylcholine was stimulated at low and inhibited at high concentrations of dibucaine and chloropromazine, for example. The mode of inhibition was seen to be competitive with respect to Ca2+, whereas stimulation by the anaesthetic drugs was independent of Ca2+. Binding between drug and enzyme was demonstrated by equilibration filtration of purified phospholipase A2 of Naja naja venom through a Sephadex G 25-fine column, previously equilibrated with 0.5 mM radioactively labelled chlorpromazine. 5. Lysophospholipase activity in rat liver cytosol towards radioactively labelled lysophosphatidylcholine was inhibited by all local anaesthetics used; the order of decreasing potency was chlorpromazine, dibucaine, tetracaine, cocaine, lidocaine and procaine. The inhibition was un-competitive with respect to substrate. 6. The inhibitory and stimulatory potencies of the local anaesthetics employed closely parallel their lipid solubilities and anaesthetic potencies.
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PMID:Effects of local anaesthetics on phospholipases. 95 85

1. Two distinct lysophospholipases have previously been obtained in homogeneous form from beef liver. In this paper, we demonstrate that ageing of a beef liver homogenate does not result in a change in the ratio of the two enzymatic activities, indicating that no interconversion of the lysophospholipases took place. 2. Possible partial structural relationships between the two enzymes were explored by immunochemical techniques. Rabbit antisera raised against each individual lysophospholipase showed no cross-reactivity with the other enzyme. This was concluded from immuno double-diffusion experiments and from the results of immunoprecipitation of enzymatic activities in solution. 3. Lysophospholipase and esterase activity in the purified preparation of lysophospholipase II from beef liver were concomitantly precipitated by anti-serum against lysophospholipase II. This is further proof that both enzymatic activities reside in a single polypeptide chain, in agreement with previous results of isoelectric focusing experiments.
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PMID:Studies on lysophospholipases. VIII. Immunochemical differences between two lysophospholipases from beef liver. 95 89

Phospholipase activity of egg-water treated Arbacia punctulata and Lytechinus variegatus sperm was shown to result from the sequential action of phospholipase A and lysophospholipase. A transient burst of phospholipase A activity followed induction of the acrosome reaction with egg water. The time of appearance suggested an acrosomal localization of the enzyme. The peak activity of phospholipase A correlated with initiation of sperm-egg fusion, suggesting a role for sea urchin sperm phospholipase A in membrane fusion and/or egg activation during fertilization.
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PMID:Phospholipase activity of sea urchin sperm: its possible involvement in membrane fusion. 97 60

Human gallbladder epithelium was disintegrated to complete loss of microscopic structure and incubated at 37 degree C together with unlabelled lysolecithin and 14C-lysolecithin. During each incubation lysolecithin was degraded and stoichiometrically equivalent amounts of free fatty acids formed. The maximum rate of degradation was obtained at pH 7.0 and at 200 muM lysolecithin. With increasing amounts of gallbladder epithelial cell constituents the reaction became faster. After heating the epithelial components at 70 degrees C for 10 min the reaction was inhibited. The results suggest the presence of a heat labile lysophospholipase (phospholipase B) activity in the human gallbladder epithelium. This activity may operate to protect the gallbladder epithelium against potentially pathogenic lysolecithin activity. Its presence in the gallbladder epithelium meets the prerequisites for a local anti-inflammatory mechanism and lends further support to the hypothesis of lysolecithin as a mediator of cholecystitis.
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PMID:The biochemical prerequisites for preventing pathogenic lysolecithin activity in the human gallbladder. 99 31

1. In a previous paper (Biochim. Biophys. Acta (1974) 369, 50-63) the purification of two proteins with lysophospholipase activity (EC 3.1.1.5), provisionally denoted lysophospholipase I and lysophospholipase II, has been described. The subcellular localization of both enzymes was investigated by cell fractionation studies. 2. For each subcellular fraction the total lysophospholipase activity, after solubilization by n-butanol treatment, was separated into a lysophospholipase I and II contribution by DEAE-Sephadex ion exchange chromatography. 3. Lysophospholipase I was found to be a soluble enzyme with a bimodal distribution. Highest relative specific activities were measured in the mitochondrial and the cytoplasmic fraction. Evidence is presented indicating that this enzyme is present in the mitochondrial matrix fraction. 4. Lysophospholipase II appeared to be a membrane-bound enzyme with highest relative specific activity in the microsomal fraction.
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PMID:Studies on lysophospholipases. IV. The subcellular distribution of two lysolecithin-hydrolyzing enzymes in beef liver. 123 15

In both supernatant and sediment of thyroid tissue homogenate phospholipase and lysophospholipase activities were demonstrated. In the supernatant, using 1-acyl-2[1-14C]linoleoyl-sn-glycero-3-phosphorocholine in the presence of sodium taurocholate, phospholipase A1 activity with pH optima at 3.6 and 4.8 and phospholipase A2 activity with pH optima at 3.6 and 5.7 were found. The sediment showed mainly phospholipase A2 activity with a pH optimum at pH 6.5. Lysophospholipase activity (optimum pH 7--8), USING 1-[9,10-(3)H]stearyl-sn-glycero-3-phosphorocholine as a substrate was present in both supernatant and sediment. Enzyme assays performed on subcellular fractions suggest the soluble phospholipases to be of lysosomal origin and the solubilized phospholipase A2 activity of homogenate sediment to be of microsomal origin. Incubations with 3H-14C mixed labelled phosphatidylcholine further confirmed the above observations.
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PMID:Phospholipases A1 and A2 in bovine thyroid. 125 88

Cyclooctatin has been isolated from Streptomyces melanosporofaciens MI614-43F2 as part of a program designed to find microorganism-produced inhibitors of lysophospholipase. It was purified by chromatography on silica gel, Capcell Pak C18 (HPLC) and Sephadex LH-20 followed by solvent extraction and then isolated as a colorless powder. Cyclooctatin has the molecular formula of C20H34O3. It is competitive with the substrate, and the inhibition constant (Ki) was 4.8 x 10(-6) M.
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PMID:Cyclooctatin, a new inhibitor of lysophospholipase, produced by Streptomyces melanosporofaciens MI614-43F2. Taxonomy, production, isolation, physico-chemical properties and biological activities. 133 49

Implantation in rabbits involves the cellular fusion of trophoblastic and uterine epithelial cells resulting in embryo penetration of the uterine endometrium. Since lysophospholipids, known to have fusigenic properties, could be responsible for this cell fusion, the metabolism of lysophospholipids was studied throughout gestation in blastocyst/yolk sac and extracoelic amnioallantoic fluids. Analysis of phospholipid composition revealed that lysophospholipids are present in blastocyst/yolk sac fluid. Their concentrations and haemolytic activity change during pregnancy. They increase and reach their highest values during days 7 to 9, the implantation days in rabbits. A clear correlation was observed between lysophosphatidylcholine concentrations in blastocyst/yolk sac fluid and haemolysis induced by this fluid. Phosphatidylcholine concentrations, phospholipase A2 activity, which generates lysophospholipids, and lysophospholipase A activity which hydrolyses lysophosphatidylcholine into fatty acid, were at their highest value at day 12. These data suggest that a transient accumulation of lysophospholipids could ensure local cell fusion. Moreover, we propose that the lysophospholipid concentrations in blastocyst/yolk sac fluid are dependent upon activities of phospholipase A2 and lysophospholipase.
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PMID:Possible implication of lysophosphatidylcholine in cell fusion accompanying implantation in rabbits. 133 61

We examined the effects of bombesin on rat pancreatic digestive enzyme gene expression using cloned complementary DNA probes for amylase, trypsinogen I, chymotrypsinogen B, and lysophospholipase. Rats were injected sc three times daily with 5 nmol/kg body wt bombesin. Pancreata were investigated after 6, 12, 24, 48, and 120 h of hormone treatment. Bombesin administration resulted in a time-dependent increase of pancreatic weight, as well as DNA and protein concentration. Cellular hypertrophy became evident after 48 h, and pancreatic hyperplasia occurred after 5 days of hormone treatment. Bombesin administration resulted in a time-dependent parallel decrease of amylase and lysophospholipase messenger RNA (mRNA) concentrations with maximal inhibition occurring after 120 h of bombesin treatment (13 +/- 1% and 14 +/- 3% of control, respectively, P less than 0.05, n = 6). In contrast, chymotrypsin and trypsin mRNA levels remained unaltered after bombesin treatment for up to 5 days. Amylase and chymotrypsin enzyme levels did not correlate with their respective mRNA concentrations. Both decreased to approximately 50% of control after 12 h and increased to 126 +/- 38% of control and 388 +/- 109% of control (P less than 0.05, n = 6), respectively, after 5 days of bombesin treatment. To test whether the bombesin regulation was mediated by the release of cholecystokinin (CCK), the specific CCK receptor antagonist L-364,718 (1 mg/kg body wt) was injected ip either alone, or 15 min before each bombesin injection for 5 days. Although the antagonist alone significantly reduced the mRNA concentrations for trypsin, chymotrypsin, and lysophospholipase to approximately 50%, it did not block the effects of bombesin on pancreatic digestive enzyme levels. These data therefore indicate that bombesin regulates pancreatic digestive enzyme mRNA and protein concentrations in a nonparallel manner; furthermore, CCK is not involved in mediating the bombesin effects on pancreatic gene expression.
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PMID:Effects of bombesin on pancreatic digestive enzyme gene expression. 137 50

The Charcot-Leyden crystal (CLC) protein, a prominent cell constituent unique to eosinophils and basophils, possesses lysophospholipase activity. This activity and the extracellular deposition and formation of CLC in tissues and body fluids in association with eosinophils suggest an extracellular function for this protein in inflammation. During degranulation, basophils release granule-derived mediators of inflammation. We postulated that CLC protein, localized in part to the basophil granule, might be released along with other mediators during this process. The extracellular release of CLC protein was studied during the degranulation of basophils stimulated by anti-immunoglobulin E (anti-IgE), N-formyl-methionyl-leucyl-phenylalanine (fMLP), phorbol myristate acetate, eosinophil major basic protein (MBP), and calcium ionophore A23187. Histamine release was used as a marker of basophil degranulation; its release was measured utilizing the fluorometric technique. CLC protein was not released into the supernatant during this process as determined by radioimmunoassay. CLC protein in the extracellular space, either as intact crystals or aggregates, was undetectable by indirect immunofluorescent staining of basophils activated with either anti-IgE or fMLP. However, upon activation, the immunofluorescent cytoplasmic and nuclear staining pattern for CLC protein was significantly altered. Decreased cytoplasmic staining and persistent or increased nuclear staining for CLC protein were observed after activation, with recovery of the preactivation, unstimulated cellular staining pattern at 30 and 45 min after stimulation with fMLP and anti-IgE, respectively. These findings suggest that CLC protein functions intracellularly in basophils during the process of activation, degranulation, and recovery. The potential nuclear function(s) of this lysophospholipase in the basophil requires further investigation.
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PMID:Charcot-Leyden crystal protein in the degranulation and recovery of activated basophils. 137 30


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