Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.1.5 (neuropathy target esterase)
 1,070 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Lysophospholipase [EC 3.1.1.5] was solubilized from the cells of Vibrio parahaemolyticus with Triton X-100 and purified by the following procedure; precipitation with ammonium sulfate, acid treatment and ion exchange column chromatography using DEAE-cellulose, DEAE-Sephadex A-50, and CM-cellulose, successively. The purified preparation was shown to be homogeneous by polyacrylamide gel disk electrophoresis. The isoelectric point of the enzyme was found to be around pH 3.64 by isoelectric focusing electrophoresis, and its molecular weight was estimated to be 89,000 at pH 7.6 by gel filtration on Sephadex G-200. The minimal molecular weight (15,000) was found at pH 3 by gel filtration on Sephadex G-100 and also by SDS-polyacrylamide disk electrophoresis. The enzyme hydrolyzed 1-acyl-GPC, 1-acyl-GPE, 2-acyl-GPE, and lysocardiolipin but did not attack monoacylglycerol, triacylglycerol, or phosphatidylcholine at all. The enzyme activity required no bivalent cations, and was unaffected by reagents specific to SH-groups, although it was inhibited by Hg2+. The enzyme activity was completely inhibited by preincubation with diisopropylfluorophosphate. The enzyme lost its activity on preincubation with either 1% SDS or 8 M urea at 37 degrees C for 30 min, but the activity lost with urea was recovered by dialysis against distilled water.
 ...
PMID:Purification of lysophospholipase of Vibrio parahaemolyticus and its properties. 2 76

Phospholipase D containing water insoluble fraction was isolated from mature barley; the enzym preparation only had weak phospholipase B activity. The phospholipase D of barley was activated by Ca2+, diethyl ether and sodium dodecyl sulphate (SDS); EDTA inhibited the enzyme to an extent of 10% of the original activity. Diethyl ether and SDS showed and additive effect. Phospholipase D activated by CaC12, diethyl ether and SDS exhibited a sharp optimum at pH 6.6. Lysophosphatidylcholine was hydrolysed much slower than phosphatidylcholine. Diethyl ether and SDS also increased the breakdown of the lysophosphatidylcholine.
 ...
PMID:[Phospholipase D of cereals (author's transl)]. 24 41

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.
 ...
PMID:Phospholipase activity of sea urchin sperm: its possible involvement in membrane fusion. 97 60

Human preimplantation embryos and endometrium secrete platelet-activating factor (PAF). The mechanism of phosphatidylcholine (PC) degradation stimulated by PAF was investigated in endometrial explants prelabeled with [methyl-3H]choline or preincubated with [3H]butan-1-ol. Analysis of the water-soluble metabolites of PAF-induced PC hydrolysis in secretory endometrium demonstrated that the stimulated generation of [3H]choline ([3H]Cho) precedes that of [3H]choline phosphate ([3H]ChoP) and [3H]glycerophosphocholine ([3H]GPC). Within 30 sec there was a rapid rise in PAF-induced [3H]Cho generation and by 2 min this had increased to 59.9% +/- 10.6% (p less than 0.02), with no effect upon [3H]ChoP and [3H]GPC during this period. Both [3H]GPC and [3H]ChoP, however, were increased at a later time point. The slower [3H]ChoP generation may suggest that PC-specific phospholipase C activation as well as delayed [3H]GPC rise may be due to PC-specific phospholipase A2 and lysophospholipase activation. Phospholipase D activity was confirmed by the incorporation of high-specific-activity [3H]butan-1-ol into [3H]phosphatidylbutanol ([3H]PBut). The rapid generation of [3H]PBut, which paralleled the rise in intracellular [3H]Cho, strongly suggests that PC breakdown is catalyzed by the phospholipase D pathway. It is proposed that PAF induces PC hydrolysis as a consequence of an early phospholipase D-catalyzed breakdown of PC in human secretory endometrium. This may be an alternative source for prostaglandin synthesis and an important pathway essential for long-term activation of local cellular events at the time of implantation.
 ...
PMID:Platelet-activating factor mediates phosphatidylcholine hydrolysis by phospholipase D in human endometrium. 163 48

Phospholipase B inhibitor was found in the autolyzate of yeast cells, Torulaspora delbrueckii. The inhibitor was purified to homogeneity by ethanol precipitation, gel filtration with Sephadex G-10, ion-exchange chromatography with DEAE-Sephacel, and gel filtration with Asahipak GS-320. On thin-layer chromatography the purified inhibitor was detected with the Hanes-Isherwood reagent, which is used to detect phosphorus. The activity of the inhibitor was not affected by heat treatment at 100 degrees C for 1 h. Heating at 100 degrees C for 1 h in 1 M HCl and 1 M NaOH lowered activity to 76 and 80% of the original values, respectively, but heating at 110 degrees C for 24 h in 6 M HCl completely abolished activity. The inhibitor was highly soluble in water, but practically insoluble in alcohol, acetone, ether, and chloroform. The degree of inhibition of enzyme activity was not proportional to the concentration of inhibitor. The inhibitor inhibited both membrane-bound and water-soluble phospholipase B activity from T. delbrueckii at the same level; however, the inhibitor did not inhibit the activity of phospholipase A2 from snake venom (Naja naja).
 ...
PMID:Isolation and fundamental characteristics of a phospholipase B inhibitor from autolyzed Torulaspora delbrueckii. 176 Jan 34

The metabolism of 1-acyl-2-acetyl-sn-glycero-3-phosphocholine (1-acyl-PAF), a naturally occurring analogue of platelet activating factor (PAF), was investigated in rabbit platelets. Our studies showed that 1-acyl-[3H]PAF (1-palmitoyl-2-acetyl-sn-glycero-3-phospho[N-methyl-3H]-choline) was converted by platelets into phosphatidyl-[3H]choline [( 3H]PC) in a time-dependent fashion. The formation of [3H]PC occurred at a rate similar to that observed when lyso-[3H]PC (palmitoyl-sn-glycero-3-phospho[N-methyl-3H]choline) was used as substrate. In addition, a time-dependent increase in the level of water-soluble radioactivity was observed during the incubation of platelets with either 1-acyl-[3H]PAF or lyso-[3H]PC. This increase was parallel to the formation of [3H]PC and was not observed in the presence of [14C]PAF (1-octadecyl-2-acetyl-sn-glycero-3-phospho[N methyl-14C]-choline). Analysis by thin-layer chromatography showed that the soluble radioactivity was mainly associated with glycerophosphocholine (GPC). On the other hand, the preincubation of platelets with phenylmethylsulfonyl fluoride, an inhibitor of the acetylhydrolase, reduced the hydrolysis of 1-acyl-[3H]PAF to [3H]GPC with a concomitant accumulation of radioactivity in 1-acyl-PAF. These findings suggest that 1-acyl-PAF is converted into PC through deacetylation-reacylation with lysoPC as an obligatory intermediate. The findings also indicate that the lysoPC resulting from 1-acyl-PAF is either reacylated to phosphatidylcholine (PC) or hydrolyzed to GPC by lysophospholipase. Finally, we showed that the stimulation of platelets with PAF led to a time- and concentration-dependent increase in the conversion of 1-acyl-[3H]PAF to [3H]PC.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:The metabolism of 1-acyl-PAF in rabbit platelets and its possible interaction with PAF. 181 55

A membrane fraction containing H,K-ATPase (EC 3.6.1.36) was prepared from pig gastric mucosa and found to contain phospholipase A2 (EC 3.1.1.4) and lysophospholipase (EC 3.1.1.5) activities. Washing the membranes decreased their protein content by 25%. Recovery profiles of H,K-ATPase, phospholipase A2 and lysophospholipase were similar for membranes washed either with water or with 0.15 or 1.5 M KCl. Nearly identical distribution profiles were obtained for the three enzyme activities after centrifugation of washed vesicle membranes on a linear sucrose gradient. The phospholipase A2 activity was stimulated by calcium and increased further in the presence of calmodulin. The amount of cellular radioactively labelled lysophosphatidylcholine was doubled upon cholinergic stimulation of isolated parietal cells prelabelled with [3H]glycerol or 32Pi. The liberated lyso[32P]phosphatidylcholine had its acyl chain in the sn-1 position, which implies an activation of a phospholipase A2. These findings indicate that secretagogues which increase the cytosolic Ca2+ concentration, i.e. acetylcholine, histamine and gastrin, may activate a phospholipase A2 in the parietal cell.
 ...
PMID:Occurrence of phospholipase A2 and lysophospholipase in a gastric H,K-ATPase-containing membrane fraction, and the formation of lysophosphatidylcholine in stimulated pig parietal cells. 196 31

Endogenous free choline levels and acetylcholine (ACh) synthesis in nerve terminals were investigated using cerebral cortical synaptosomes of C57BL/6 mice. Endogenous choline was produced at a rate ten-fold faster than ACh to provide levels adequate for the formation of the latter. The combined pool size of the water-soluble intermediates derived from phosphatidylcholine (PhC), such as glycerophosphorylcholine (GpCh) and phosphorylcholine (PCh), increased significantly during the first 10-15 min of incubation and was always higher than that of free choline. These results most likely indicate an effective degradation of PhC by the combined action of phospholipase A2/lysophospholipase, as well as by phospholipase C in synaptosomes. ACh synthesis proceeded at a constant rate in the presence or absence of exogenous free choline (0-10 microM) and was almost entirely abolished in the presence of 10(-6) M hemicholinium-3. These results suggest that ACh is effectively synthesized by free choline generated in synaptosomes by a coupling mechanism involving the high-affinity choline uptake system. No changes in the production rates of choline and ACh were observed between adult and aged mice.
 ...
PMID:Phospholipid-derived choline intermediates and acetylcholine synthesis in mouse brain synaptosomes. 258 48

The Staphylococcus hyicus lipase gene has been cloned and expressed in Staphylococcus carnosus. From the latter organism the enzyme was secreted into the medium as a protein with an apparent molecular mass of 86 kDa. This protein was purified, and the amino-terminal sequence showed that the primary gene product was indeed cleaved at the proposed signal peptide cleavage site. The protein was purified from large-scale preparations after tryptic digestion. This limited proteolysis reduced the molecular mass to 46 kDa and increased the specific activity about 3-fold. Although the enzyme had a low specific activity in the absence of divalent cations, the activity increased about 40-fold in the presence of Sr2+ or Ca2+ ions. The purified lipase has a broad substrate specificity. The acyl chains were removed from the primary and secondary positions of natural neutral glycerides and from a variety of synthetic glyceride analogues. Thus triglycerides were fully hydrolyzed to free fatty acid and glycerol. The enzyme hydrolyzed naturally occurring phosphatidylcholines, their synthetic short-chain analogues, and lysophospholipids to free fatty acids and water-soluble products. The enzyme had a 2-fold higher activity on micelles of short-chain D-lecithins than on micelles composed of the L-isomers. Thus the enzyme from S. hyicus has lipase activity and also high phospholipase A and lysophospholipase activity.
 ...
PMID:Purification and substrate specificity of Staphylococcus hyicus lipase. 261 Dec 29

The phospholipase activity of rat jejunal brush-border membranes was examined in the presence of several solubilizing agents, by measuring the hydrolysis of endogenous membrane phospholipids, as well as the hydrolysis of exogenous, radiolabelled substrates. Enzyme activity was highly stimulated by dispersion in 1% solutions of bile salts, or in a synthetic, bile-salt derivative, 3-[(3-cholamidopropyl)dimethylammonio]propanesulphonate (CHAPS). Under these conditions the endogenous membrane phospholipids were largely degraded to free fatty acids and water-soluble phosphate. In the presence of 1% CHAPS, hydrolysis of exogenous phosphatidylcholine was shown to be due to an initial phospholipase A2-type attack followed by a subsequent lysophospholipase-type attack. These activities co-purified with the brush-border membrane. Maximal phospholipase A2 hydrolysis occurred at an alkaline pH of 8-11, with bile-salt detergents present at greater than their critical micellar concentrations. Hydrolysis was completely divalent-ion independent. Phospholipase A2 activity was not stimulated by 50% diethyl ether or ethanol, or in the presence of 1% solutions of Triton X-100, Zwittergent 3-12, sodium dodecyl sulphate, or n-octylglucoside. Stimulation of phospholipase activity by detergents was not related to their effectiveness at solubilizing the membrane proteins. When assayed individually phosphatidylcholine and lysophosphatidylcholine were each hydrolyzed (at the sn-2 and sn-1 positions, respectively) at a rate of approximately 125 nmol/mg protein per min. When assayed together, the two substrates appeared to compete for the same active site over a wide range of concentrations. It was concluded that the brush-border membrane contains an integral membrane protein with phospholipase A2 and lysophospholipase activities, which is specifically stimulated by bile salts and bile salt-like detergents.
 ...
PMID:Solubilization and assay of phospholipase A2 activity from rat jejunal brush-border membranes. 334 32


1 2 3 4 Next >>