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)

Long-chain N-acylethanolamines (NAEs) elicit a variety of biological and pharmacological effects. Anandamide (20:4n-6 NAE) and other polyunsaturated NAEs bind to the cannabinoid receptor and may thus serve as highly specific lipid mediators of cell signalling. NAEs can be formed by phospholipase D-catalyzed hydrolysis of N-acylethanolamine phospholipids or by direct condensation of ethanolamine and fatty acid. So far, most of the latter biosynthetic activity has been shown to be the reverse reaction of the NAE amidohydrolase that catalyzes NAE degradation. Thus, increasing evidence supports the hypothesis that the N-acylation-phosphodiesterase pathway yields not only saturated-monounsaturated NAEs, but polyunsaturated ones, including anandamide, as well.
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PMID:The N-acylation-phosphodiesterase pathway and cell signalling. 868 24

Cannabinoid receptors have been described in sea urchin sperm and shown to mediate inhibition of sperm acrosome reaction. Anandamide (arachidonoyl-ethanolamide), the mammalian physiological ligand at the cannabinoid CB1 receptor, has been subsequently found to effect this inhibition. Here we present data showing that ovaries from the sea urchin Paracentrotus lividus contain anandamide and two related acyl-ethanolamides, as well as enzymatic activities potentially responsible for their biosynthesis and degradation. Pilot experiments carried out with either ovaries or spermatozoa, extracted from both P. lividus and Arbacea lixula and radiolabelled with [14C]ethanolamine, showed that in sexually mature ovaries of both species significant levels of radioactivity were incorporated into a lipid component with the same chromatographic behaviour as anandamide. Lipid extracts from P. lividus ovaries were purified and analysed by gas chromatography/mass spectrometry which showed the presence of low but measurable amounts of anandamide, palmitoyl- and stearoyl-ethanolamides. The extracts were also found to contain lipid components with the same chromatographic behaviour as the N-acyl-phosphatidyl-ethanolamines, the phospholipid precursors of acyl-ethanolamides in mammalian tissues, and capable of releasing anandamide, palmitoyl- and stearoyl-ethanolamides upon digestion with S. chromofuscus phospholipase D. Accordingly, whole homogenates from P. lividus contained an enzymatic activity capable of converting synthetic [3H]N-arachidonoyl-phosphatidyl-ethanolamine into [3H]anandamide. Finally, mature ovaries of P. lividus were shown also to contain an amidohydrolase activity which catalyses the hydrolysis of anandamide and palmitoyl-ethanolamide to ethanolamine. This enzyme displayed subcellular distribution, pH/temperature dependency profiles and sensitivity to inhibitors similar but not identical to those of the previously described 'anandamide amidohydrolase' from mammalian tissues. These data support the hypothesis, formulated in previous studies, that anandamide or related metabolites may be oocyte-derived cannabimimetic regulators of sea urchin fertility.
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PMID:Occurrence and metabolism of anandamide and related acyl-ethanolamides in ovaries of the sea urchin Paracentrotus lividus. 915 Feb 53

Recently, the biosynthesis of an unusual membrane phospholipid, N-acylphosphatidylethanolamine (NAPE), was found to increase in elicitor-treated tobacco (Nicotiana tabacum L.) cells (K.D. Chapman, A. Conyers-Hackson, R.A. Moreau, S. Tripathy [1995] Physiol Plant 95: 120-126). Here we report that before induction of NAPE biosynthesis, N-acylethanolamine (NAE) is released from NAPE in cultured tobacco cells 10 min after treatment with the fungal elicitor xylanase. In radiolabeling experiments [14C]NAE (labeled on the ethanolamine carbons) increased approximately 6-fold in the culture medium, whereas [14C]NAPE associated with cells decreased approximately 5-fold. Two predominant NAE molecular species, N-lauroylethanolamine and N-myristoylethanolamine, were specifically identified by gas chromatography-mass spectrometry in lipids extracted from culture medium, and both increased in concentration after elicitor treatment. NAEs were found to accumulate extracellularly only. A microsomal phospholipase D activity was discovered that formed NAE from NAPE; its activity in vitro was stimulated about 20-fold by mastoparan, suggesting that NAPE hydrolysis is highly regulated, perhaps by G-proteins. Furthermore, an NAE amidohydrolase activity that catalyzed the hydrolysis of NAE in vitro was detected in homogenates of tobacco cells. Collectively, these results characterize structurally a new class of plant lipids and identify the enzymatic machinery involved in its formation and inactivation in elicitor-treated tobacco cells. Recent evidence indicating a signaling role for NAPE metabolism in mammalian cells (H.H.O. Schmid, P.C. Schmid, V. Natarajan [1996] Chem Phys Lipids 80: 133-142) raises the possibility that a similar mechanism may operate in plant cells.
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PMID:N-Acylethanolamines: formation and molecular composition of a new class of plant lipids 950 Nov 49

In mouse neuroblastoma N18TG2 cells prelabeled with [3H]arachidonic acid ([3H]AA) the biosynthesis of 2-arachidonoylglycerol (2-AG) is induced by ionomycin in a fashion sensitive to an inhibitor of diacylglycerol (DAG) lipase, RHC 80267, but not to four different phospholipase C (PLC) blockers. Pulse experiments with [3H]AA showed that ionomycin stimulation leads to the sequential formation of [3H]phosphatidic acid ([3H]PA), [3H]DAG, and [3H]2-AG. [3H]2-AG biosynthesis in N18TG2 cells prelabeled with [3H]AA was counteracted by propranolol and N-ethylmaleimide, two inhibitors of the Mg2+/Ca2(+)-dependent brain PA phosphohydrolase. Pretreatment of cells with exogenous phospholipase D (PLD) led to a strong potentiation of ionomycin-induced [3H]2-AG formation. These data indicate that DAG precursors for 2-AG in intact N18TG2 cells are obtained from the hydrolysis of PA and not through the activation of PLC. The presence of 2% ethanol during ionomycin stimulation failed to elicit the synthesis of [3H]phosphatidylethanol and did not counteract the formation of [3H]PA, thus arguing against the activation of PLD by the Ca2+ ionophore. Selective inhibitors of secretory phospholipase A2 and the acyl-CoA acylase inhibitor thimerosal significantly reduced [3H]2-AG biosynthesis. The implications of these latter findings, and of the PA-dependent pathways of 2-AG formation described here, are discussed.
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PMID:Phosphatidic acid as the biosynthetic precursor of the endocannabinoid 2-arachidonoylglycerol in intact mouse neuroblastoma cells stimulated with ionomycin. 1021 92

Adenosine (Ado) is an important autocrine modulator of neutrophil functions. In this study, we determined the effects of endogenous Ado on fMet-Leu-Phe (fMLP)-induced phospholipase D (PLD) activity in neutrophils. The removal of extracellular Ado by Ado deaminase (ADA) or the blockade of its action by the A2a receptor antagonists 8-(3-chlorostyryl) caffeine (CSC) or CGS15943 markedly increased fMLP-induced PLD activation. The concentration-dependent stimulatory effects of CSC and CGS15943 were abolished by a pretreatment of neutrophil suspensionswith ADA. In contrast, the selective A2a receptor agonist CGS21680 suppressed fMLP-induced PLD activation. Furthermore, inhibition by CGS21680 of fMLP-induced PLD activity was reversed by CSC or CGS15943. The removal of Ado by ADA or the blockade of its action by CSC or CGS15943, markedly increased the membrane recruitment of cytosolic protein kinase Calpha (PKCalpha), RhoA, and ADP-ribosylation factor (ARF) in response to fMLP. As shown for PLD activity, the stimulatory effect of Ado receptor antagonists on PLD cofactors translocation was abolished by a pretreatment of the cells with ADA. Moreover, the membrane translocation of both PKCalpha, RhoA, and ARF in response to fMLP was attenuated by CGS21680 and this effect of the A2a receptor agonist was antagonized by CSC or CGS15943. These data demonstrate that Ado released by neutrophils in the extracellular milieu inhibits PLD activation by blocking membrane association of ARF, RhoA, and PKCalpha through Ado A2a receptor occupancy. (Blood. 2000;95:519-527)
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PMID:Adenosine receptor occupancy suppresses chemoattractant-induced phospholipase D activity by diminishing membrane recruitment of small GTPases. 1062 57

Macrophage-derived endocannabinoids have been implicated in endotoxin (lipopolysaccharide (LPS))-induced hypotension, but the endocannabinoid involved and the mechanism of its regulation by LPS are unknown. In RAW264.7 mouse macrophages, LPS (10 ng/ml) increases anandamide (AEA) levels >10-fold via CD14-, NF-kappaB-, and p44/42-dependent, platelet-activating factor-independent activation of the AEA biosynthetic enzymes, N-acyltransferase and phospholipase D. LPS also induces the AEA-degrading enzyme fatty acid amidohydrolase (FAAH), and inhibition of FAAH activity potentiates, whereas actinomycin D or cycloheximide blocks the LPS-induced increase in AEA levels and N-acyltransferase and phospholipase D activities. In contrast, cellular levels of the endocannabinoid 2-arachidonoylglycerol (2-AG) are unaffected by LPS but increased by platelet-activating factor. LPS similarly induces AEA, but not 2-AG, in mouse peritoneal macrophages where basal AEA levels are higher, and the LPS-stimulated increase in AEA is potentiated in cells from FAAH-/- as compared with FAAH+/+ mice. Intravenous administration of 107 LPS-treated mouse macrophages to anesthetized rats elicits hypotension, which is much greater in response to FAAH-/- than FAAH+/+ cells and is susceptible to inhibition by SR141716, a cannabinoid CB1 receptor antagonist. We conclude that AEA and 2-AG synthesis are differentially regulated in macrophages, and AEA rather than 2-AG is a major contributor to LPS-induced hypotension.
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PMID:Lipopolysaccharide induces anandamide synthesis in macrophages via CD14/MAPK/phosphoinositide 3-kinase/NF-kappaB independently of platelet-activating factor. 1294 78

We have constructed a genome-saturating mutant library of the human gastric pathogen Helicobacter pylori. Microarray tracking of transposon mutants (MATT) allowed us to map the position of 5,363 transposon mutants in our library. While we generally found insertions well distributed throughout the genome, 344 genes had no detectable transposon insertions, and this list is predicted to be highly enriched for essential genes. Comparison to the essential gene set of other bacteria revealed a surprisingly limited overlap with all organisms tested (11%), while 55% were essential in some organisms but not others. We independently verified the essentiality of several gene products, including an HtrA family serine protease, a hypothetical protein with putative phospholipase D activity, and a riboflavin specific deaminase. A limited screen for motility mutants allowed us to estimate that 4.5% of the genome is dedicated to this virulence-associated phenotype.
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PMID:Global transposon mutagenesis and essential gene analysis of Helicobacter pylori. 1554 64

Anandamide (N-arachidonoylethanolamine) is the first discovered endocannabinoid (endogenous ligand of cannabinoid receptors). In animal tissues, anandamide is principally formed together with other bioactive long-chain N-acylethanolamines from membrane glycerophospholipid by two enzyme reactions. The first reaction is the transfer of a fatty acyl chain from the sn-1 position of glycerophospholipid to phosphatidylethanolamine by calcium-dependent N-acyltransferase, resulting in the generation of N-acylphosphatidylethanolamine (NAPE). The second reaction is catalyzed by a phosphodiesterase of the phospholipase D (PLD)-type, which releases N-acylethanolamines from their corresponding NAPEs. The produced N-acylethanolamines are hydrolyzed to fatty acids and ethanolamine by fatty acid amide hydrolase or an amidase acting exclusively at acidic pH. Our recent cDNA cloning of the NAPE-hydrolyzing PLD (NAPE-PLD) from mouse, rat and human revealed that NAPE-PLD is a novel enzyme which has no homology with any known PLD enzymes, but belongs to the zinc metallo-hydrolase family of the beta-lactamase fold. The recombinant enzyme hydrolyzed various NAPEs, including the anandamide precursor N-arachidonoylphosphatidylethanolamine at similar rates, but was inactive with phosphatidylcholine and phosphatidylethanolamine. Considering cannabimimetic activities of anandamide, the enzymes involved in the biosynthesis and degradation of anandamide, including NAPE-PLD, may be promising targets for therapeutic agents.
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PMID:Endocannabinoid-related enzymes as drug targets with special reference to N-acylphosphatidylethanolamine-hydrolyzing phospholipase D. 1597 92

The endogenous cannabinoid acylethanolamide AEA (arachidonoylethanolamide; also known as anandamide) participates in the neuroadaptations associated with chronic ethanol exposure. However, no studies have described the acute actions of ethanol on AEA production and degradation. In the present study, we investigated the time course of the effects of the intraperitoneal administration of ethanol (4 g/kg of body mass) on the endogenous levels of AEA in central and peripheral tissues. Acute ethanol administration decreased AEA in the cerebellum, the hippocampus and the nucleus accumbens of the ventral striatum, as well as in plasma and adipose tissue. Parallel decreases of a second acylethanolamide, PEA (palmitoylethanolamide), were observed in the brain. Effects were observed 45-90 min after ethanol administration. In vivo studies revealed that AEA decreases were associated with a remarkable inhibition of the release of both anandamide and glutamate in the nucleus accumbens. There were no changes in the expression and enzymatic activity of the main enzyme that degrades AEA, the fatty acid amidohydrolase. Acute ethanol administration did not change either the activity of N-acyltransferase, the enzyme that catalyses the synthesis of the AEA precursor, or the expression of NAPE-PLD (N-acylphosphatidylethanolamine-hydrolysing phospholipase D), the enzyme that releases AEA from membrane phospholipid precursors. These results suggest that receptor-mediated release of acylethanolamide is inhibited by the acute administration of ethanol, and that this effect is not derived from increased fatty acid ethanolamide degradation.
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PMID:Regulation of brain anandamide by acute administration of ethanol. 1730 58

Investigations of the pathways involved in the metabolism of endocannabinoids have grown exponentially in recent years following the discovery of cannabinoid receptors (CB) and their endogenous ligands, such as anandamide (AEA) and 2-arachidonoylglycerol (2-AG). The in vivo biosynthesis of AEA has been shown to occur through several pathways mediated by N-acylphosphatidylethanolamide-phospholipase D (NAPE-PLD), a secretory PLA(2) and PLC. 2-AG, a second endocannabinoid is generated through the action of selective enzymes such as phosphatidic acid phsophohydrolase, diacylglycerol lipase (DAGL), phosphoinositide-specific PLC (PI-PLC) and lyso-PLC. A putative membrane transporter or facilitated diffusion is involved in the cellular uptake or release of endocannabinoids. AEA is metabolized by fatty acid amidohydrolase (FAAH) and 2-AG is metabolized by both FAAH and monoacylglycerol lipase (MAGL). The author presents an integrative overview of current research on the enzymes involved in the metabolism of endocannabinoids and discusses possible therapeutic interventions for various diseases, including addiction.
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PMID:Critical enzymes involved in endocannabinoid metabolism. 1734 27


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