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. Rat stomach mucosa exhibited three distinguishable phospholipid-deacylating enzyme activities: lysophospholipase, phospholipase A1 and phospholipase A2. 2. The lysophospholipase hydrolyzed 1-palmitoyl lysophosphatidylcholine to free fatty acid and glycerophosphorylcholine. This enzyme had an optimum pH of 8.0, was heat labile, did not require Ca2+ for maximum activity and was not inhibited by bile salts or buffers of high ionic strength. 3. Phospholipase A2 and phospholipase A1 deacylated dipalmitoyl phophatidylcholine to the corresponding lyso compound and free fatty acid. The specific activity of phospholipase A2 was 2--4-fold higher than that of phospholipase A1 under all the conditions tested. Both activities were enhanced 4--7.5-fold in the presence of bile salts at alkaline pH and 11-18-fold at acidic pH. 4. In the absence of bile salts, phospholipase A1 exhibited pH optima at 6.5 and 9.5 and phospholipase A2 at pH 6.5, 8.0 and 9.5. The pH optima for phospholipase A1 were shifted to pH 3.0, 6.0 and 9.0 in presence of sodium taurocholate; the activity was detected only at a single pH of 9.5 in the presence of sodium deoxycholate and at pH 10.0 in the presence of sodium glycocholate. Phospholipase A2 optimum activity was displayed at pH 3.0, 6.0 and 8.0 in presence of taurocholage, pH 7.5 and 9.0, in presence of glycocholate and only at pH 9.0 in presence of deoxycholate. 5. Ca2+ was essential for optimum activity of phospholipases A1 and A2. But phospholipase A1 lost complete activity in presence of 0.5 mM ethyleneglycolbis-(beta-aminoethylether)-N,N'-tetraacetic acid (EGTA) at pH 6.0, whereas phospholipase A2 lost only 50%. 6. Phospholipases A1 and A2 retained about 50% of their activities by heating at 75 degrees for 10 min. At 100 degrees, phospholipase A1 retained 22% of its activity, whereas phospholipase A2 retained only 7%.
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PMID:Phospholipid-deacylating enzymes of rat stomach mucosa. 63 60

The positional specificity of the phospholipase A in human gallbladder epithelium was studied by using biosynthetically radioabeled diacylphosphoglycerides as substrates. Diacylphosphoglyceride in 14C-palmitic acid-labeled, autoclaved E.coli was hydrolyzed under the formation of monoacylphosphoglyceride and fatty acid that were both radiolabled. In contrast, diacylphosphoglyceride in 14C-oleate-labeled bacteria was hydrolyzed so as to give radiolabel in the fatty acid only. Since 14C-palmitate occupies predominantly the 1-acyl position and 14C oleate the 2-acyl position of the major E. coli diacylphosphoglycerides, these findings suggest that: 1) the phospholipase attacks and 2-position of diacylphosphoglycerides, and 2) a complete deacylation of diacylphosphoglycerides in the gallbladder wall is brought about by the combined action of phospholipase A2 and lysophospholipase, the latter being able to hydrolyze the 1-acyllysophosphoglyceride. It appears, therefore, that the biochemical preequisites for a local formation and degreadation of lysolecithin in the gallbladder itself are met by the positional specificity of theenzymes present. This finding further substantiates the hypothesis that lysolecithin is an adjustable mediator of aseptic cholecystitis.
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PMID:The prerequisites for local lysolecithin formation in the human gallbladder. II. Studies on the positional specificity of the phospholipase A activity. 67 50

Heat-induced inhibition of erythrocyte sedimentation (HIES) was examined in 158 cases. HIES is significantly lower in patients with a liver cell damage isolated or due to metastases of a neoplastic process in comparison to that in patients suffering from inflammation or malign tumor not involving the liver. Generally, HIES depends upon the concentration of lysophosphatidyl choline (lysolecithin) which is set free in plasma by lecithin-cholesterol-acyltransferase (LCAT) during incubation. In patients with lever cell damage, LCAT is diminished. HIES is being influenced by several factors: Lysophosphatidyl choline is bound to albumin, and this prevents its reaction on the erythrocyte surface. Lysophospholipase reduces the concentration of lysophosphatidyl choline in the plasma by splitting off its fatty acid in the alpha-position. Specific serum proteins, the so-called agglomerines, which are responsible for the acceleration of erythrocyte sedimentation, are counteracting the HIES. The concentration of albumin and agglomerines in plasma and the activity of lysophospholipase are subject to physiologically and pathologically caused deviations. Thereby, HIES is being influenced individually at varying degrees. This makes it difficult to estimate the LCAT activity which represents the principal cause of HIES. As a consequence, HIES seems not to be suitable for clinical diagnostics.
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PMID:[Diagnostic significance of heat-induced inhibition of erythrocyte sedimentation (author's transl)]. 71 17

1. The composition and metabolism of phospholipids were studied in various tissues from both normal and dystrophic mice of the 129 ReJ strain. Phospholipids extracted from forebrain, spinal cord, sciatic nerve and plasma were fractionated by t.l.c. and measured. 2. Very significant alterations were found in the choline phospholipids from these tissues, except forebrain. Plasma phosphatidylcholine in the dystrophic mouse was increased by 38%. There was a 2-fold increase in lysophosphatidylcholine in the spinal cord of dystrophic mice. The sciatic nerve showed a marked decrease in sphingomyelin content, which is approximately half of that in the controls. 3. Five enzymes involved in phosphatidylcholine metabolism [namely cholinephosphotransferase (EC 2.7.8.2); phospholipases A (EC 3.1.1.4, EC 3.1.1.32); lysophospholipase (EC 3.1.1.5); lysophosphatidylcholine acyltransferase (EC 2.3.1.23); phospholipase C (EC 3.1.4.3)] were studied in tissue preparations from forebrain, spinal cord, sciatic nerves, gastrocnemius muscles and liver. 4. Activities of phospholipases A and C were significantly increased, about 5-fold and 60% respectively, in gastrocnemius muscle of dystrophic mice compared with controls. Phospholipases A also showed 50% higher activity in the sciatic nerves of dystrophic than of normal mice. Lysophosphatidylcholine acyltransferase activities were significantly increased in the sciatic nerves and spinal cord, by 50-100% over that of the controls. The forebrain and spinal cord from dystrophic mice, however, had only 60% of lysophospholipase activities of that of the normal control. Cholinephosphotransferase activity was unchanged in these tissues from both normal and dystrophic mice. 5. It is suggested that are number of features of mouse muscular dystrophy related to altered membrane structure and function can be rationalized in terms of changes in lipid composition and metabolism.
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PMID:Phospholipid composition and metabolism in mouse muscular dystrophy. 72 3

Single bilayer vesicles were prepared from total rat liver microsomal lipids to which 5 mol% lysophosphatidylcholine had been added. The availability of lysophosphatidylcholine for enzymatic hydrolysis by lysophospholipase (EC 3.1.1.5) was found to be higher in vesicles prepared by the cholate dispersion technique when compared with sonicated vesicles. Sepharose 4 B chromatography showed that the vesicles prepared by the cholate technique were smaller than those prepared by sonication. This is in contrast to previous observations for egg phosphatidylcholine vesicles. Total rat liver microsomal extracts were found to contain proteolipid, which could be removed by ether precipitation. Cholate vesicles prepared from proteolipid-free extracts were still smaller than sonicated vesicle from this extract. Experiments with [14C] dextran entrapped in the vesicles indicate that there is no loss of the permeability barrier of the vesicles for high molecular weight solutes during vesicle treatment with lysophospholipase. The high availability of lysophosphatidylcholine in cholate vesicles of total rat liver microsomal lipids is discussed in terms of a highly asymmetric distribution of lysophosphatidylcholine over the inner and outer monolayer of the bilayer.
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PMID:Availability of lysophosphatidylcholine in single bilayer vesicles for hydrolysis by lysophospholipase. 75 Aug 31

The cell envelope of Neisseria gonorrhoeae, colony type 4, was studied. Outer membrane was isolated by lysozyme and ethylenediaminetetraacetic acid treatment of plasmolyzed cells according to Wolf-Watz et al. (1973). The degree of purity of the membrane preparations was checked by electron microscopy. The membrane fraction obtained had a density of 1.25 g/cm(3), was rich in phospholipase A and lysophospholipase, and contained only 10% of the total membrane activity of succinate dehydrogenase and d-lactate dehydrogenase. The outer membrane protein profile after sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed at least six major proteins. The predominating protein showed a molecular weight of 35,000. The lipopolysaccharide component was characterized by gas chromatography. The carbohydrates found were galactose, glucose, and glucosamine. d-Glycero-l-manno-heptose was present in very low amounts. Lipid A contained lauric acid, stearic acid, and beta-hydroxy-myristic acid. About 20% of the fatty acids in the outer membrane was derived from lipid A. The phospholipids were characterized as phosphatidylethanolamine, phosphatidylglycerol, and diphosphatidylglycerol. There was no evidence for a lipoprotein anchored to the peptidoglycan. The peptidoglycan of N. gonorrhoeae was of the chemotype I. The cell envelope of N. gonorrhoeae was found to be highly permeable to gentian violet. Cell envelopes of one penicillin-resistant and two penicillin-sensitive strains were compared. Only moderate differences in fatty acid composition were found.
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PMID:Cell envelope of Neisseria gonorrhoeae: outer membrane and peptidoglycan composition of penicillin-sensitive and-resistant strains. 80 26

Single bilayer vesicles were prepared by sonication of 5 mol% 1-palmitoyl lysophosphatidylcholine and 95 mol% egg phosphatidylcholine. Incubation with lysophospholipase results in a fast hydrolysis of 80-90% of lysophosphatidylcholine. The remaining lysophosphatidylcholine is only very slowly hydrolysed. There results are interpreted as lysophosphatidylcholine being asymmetrically distributed over the two halves of the bilayer. The slow phase of lysophosphatidylcholine hydrolysis sets an upper limit to the rate of transbilayer movement of lysophosphatidylcholine. The half time of this process at 37 degrees C is estimated to be about 100 h. Incorporation of cholesterol in the vesicles reduces the distributional asymmetry of lysophosphatidylcholine to the extent of an outside-inside ratio of 60 : 40 [14C]Lysophosphatidylcholine introduced into the outer monolayer of such vesicles by intervesicular transfer of lysophosphatidylcholine remains virtually completely available for hydrolysis by lysophospholipases, corroborating the interpretation that transbilayer movement of lysophosphatidylcholine in these vesicles is an extremely slow process. In handshaken liposomes consisting of 5 mol% 1-palmitoyl lysophosphatidylcholine and 95 mol% egg phosphatidylcholine 15-20% of lysophosphatidylcholine is readily available for exogenous lysophospholipase. This pool may represent lysophosphatidylcholine in the outer monolayer of the liposomes.
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PMID:Transbilayer distribution and movement of lysophosphatidylcholine in liposomal membranes. 83 37

Incubation of rat lung supernatant with 1-[1(-14)C] palmitoyl-sn-glycero-3-phosphocholine in the absence of any cofactors resulted in the release of radioactive fatty acid and the formation of phosphatidylcholine. The production of fatty acids (lysophospholipase activity) exceeded phosphatidylcholine formation (transacylase activity) about thereefold, although the relative extent of phosphatidylcholine formation was considerably greater than previously reported by Abe et al. (Biochim. Biophys. Acta, 369: 361-370, 1974). In agreement with these authors, evidence is presented suggesting that a single enzyme is responsible for both catalytic activities. The enzyme, provisionally denoted lysophospholipase-transacylase, was found primarily in the soluble fraction of rat lung and was purified approximately 250-fold. The enzyme had an estimated mol wt of 50,000. The ratio of lysophospholipase to transacylase activity in the purified enzyme could be varied depending upon the concentration and character of the lysophosphatidylcholine and the ration of substrate to products. The degree of esterification of 1-acyl lysophosphatidylcholine was altered with mixtures of different molecular species of substrate, indicating acyl chain selectivity in the transfer process. This enzyme was capable of synthesizing disaturated phosphatidylcholine, an important component of the pulmonary surfactant. Three lysophospholipases purified from other sources did not possess this transacylase activity.
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PMID:Lysophospholipase--transacylase from rat lung: isolation and partial purification. 89 43

The cholate method originally introduced by Kagawa et al. (J. Biol. Chem. (1973) 248, 676-684) and further developed by Brunner et al. (Biochim. Biophys. Acta (1976) 455, 322-331) has been used to prepare single bilayer vesicles containing 5 mol% lysophosphatidylcholine embedded in a matrix of phosphatidylcholine. The distribution of lysophosphatidylcholine over outer and inner monolayer was found to be highly asymmetric (ratio 9:1), as determined by lysophospholipase treatment of the vesicles. This distribution is similar to the value found in sonicated vesicles. Up to 20 mol% cholesterol could be incorporated in the vesicles by the cholate method. The method was succesfully used also for the preparation of single bilayer vesicles from total rat liver microsomal lipids, to which 5 mol% of 1-[1-14C]palmitoyl lysophosphatidylcholine had been added. Surprisingly, almost 100% of lysophosphatidylcholine in the latter vesicles was directly available for hydrolysis by sophospholipase. In contrast, only 70% of the lysophosphatidylcholine is sonicated vesicles of similar composition could be hydrolyzed by lysophospholipase.
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PMID:Distribution of lysophosphatidylcholine in single bilayer vesicles prepared without sonication. 92 89

It has been possible to demonstrate and characterize high phospholipase activities in mycelia of Rhizopus arrhizus and Mucor javanicus by use of a system in which substrates were dissolved in diisopropyl ether. Such activities were associated with bound enzymes and would have been difficult to detect using aqueous assay systems. In both cases, phosphatidylcholine hydrolysis was by phospholipase A1 (EC 3.1.1.32) activity followed by the action of lysophospholipase (EC 3.1.1.5). Phospholipase D (EC 3.1.4.4) activity was also detected. The methods used appear to be of general applicability for the detection and study of insoluble phospholipases.
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PMID:Study of bound phospholipase activities of fungal mycelia using an organic solvent system. 94 51


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