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)

The hydrolysis of the alkenyl bonds of plasmenylcholine and plasmenylethanolamine by plasmalogenase, followed by hydrolysis of the resultant lysophospholipid by lysophospholipase, has been postulated as the major pathway for the catabolism of these plasmalogens. However, the postulation was based solely on the presence of plasmalogenase activity towards plasmenylethanolamine and plasmenylcholine in the brain. In this study we have demonstrated the absence of plasmalogenase activity for plasmenylcholine in the guinea pig heart under a wide range of experimental conditions. Plasmenylcholine was hydrolysed by phospolipase A2 activities in cardiac microsomal, mitochondrial and cytosolic fractions. Phospholipase A2 activities in these fractions had an alkaline pH optimum and were enhanced by Ca2+. The enzymes also displayed high specificity for plasmenylcholine with linoleoyl or oleoyl at the C-2 position. Lysoplasmalogenase activity for lysoplasmenycholine was also detected and characterized in the microsomal and mitochondrial fractions. Since the cardiac plasmalogenase is only active towards plasmenylethanolamine but not plasmenylcholine, the catabolism of these two plasmalogens must be different from each other. We postulate that the major pathway for the catabolism of plasmenycholine involves the hydrolysis of the C-2 fatty acid by phospholipase A2, and hydrolysis of the vinyl ether group of the resultant lysoplasmenylcholine by lysoplasmalogenase.
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PMID:The catabolism of plasmenylcholine in the guinea pig heart. 375 61

Phospholipase A2 and lysophospholipase activities were detected in the culture supernatant fluids of a virulent strain of Vibrio vulnificus. The phospholipase A2 was inactivated by heating at 56 degrees C for 30 min, had an apparent molecular weight of greater than or equal to 80,000 (estimated by gel filtration with Sephadex G-75), and a pI of ca. 5.0. Phospholipid hydrolysis was unaffected by Ca2+ or ethylene glycol-bis(beta-aminoethyl ether)-N,N-tetraacetic acid and was optimal at pH 5.0 to 5.5. The lysophospholipase was not affected by heating at 56 degrees C for 30 min but was inactivated at 100 degrees C and had an apparent molecular weight of greater than or equal to 80,000 and a pI of ca. 4.0. The enzymes were detected coincidentally with a previously described extracellular cytolysin of V. vulnificus; however, they were physically separable from the toxin (which did not possess phospholipase A, C, or D activity) by gel filtration with Sephadex G-75.
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PMID:Extracellular phospholipase A2 and lysophospholipase produced by Vibrio vulnificus. 674

Membrane-bound neuropathy target esterase (NTE) and associated phenyl valerate carboxylesterases were solubilized from chicken embryo brain by phospholipase A2. Phospholipase A2 from bee or cobra (Naja) venoms were the most effective preparations in solubilizing brain NTE and other phenyl valerate carboxylesterases. Phospholipase C and several proteinases (endoproteinase, pronase E, proteinase K, thermolysin, trypsin) did not solubilize brain membrane-bound carboxylesterases but reduced their activity. NTE solubilization by phospholipase A2 did not affect its apparent Km and Vmax for the substrate phenyl valerate or the susceptibility of phenyl valerate carboxylesterases to inhibition by paraoxon and mipafox. NTE thermal stability diminished after the treatment of brain membrane fragments with phospholipase A2.
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PMID:Solubilization of neuropathy target esterase and other phenyl valerate carboxylesterases from chicken embryonic brain by phospholipase A2. 788 4

Leaves of higher plant Vicia faba contains two Phospholipase A2 (PLA2) activities which are detected in cytosolic fractions. Based on a gel filtration column chromatography, two cytosolic PLA2 activities migrated with molecular masses of 70 kDa and 14 kDa. The first (70 kDa peak) was optimally active at pH 4.5 and was not dependent on [Ca2+] for its activity. In the presence of 5 mM CaCl2, 'phospholipase B' activity was shown in the 70 kDa peak. The second (14 kDa peak) was optimally active in the pH range 9-10 and required millimolar concentrations of calcium for optimal activity. The two activities were not inhibited by dithiothreitol. Neither anti-pancreatic PLA2 antiserum nor anti-(pig spleen 100 kDa cytosolic PLA2) antiserum immunoprecipitated any activity of the two plant PLA2's. The present results indicate that at least the 14 kDa form of the two PLA2 enzymes detected in leaves of higher plants is biochemically and immunochemically different from the well characterized Ca(2+)-dependent mammalian PLA2's.
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PMID:Detection of two phospholipase A2(PLA2) activities in leaves of higher plant Vicia faba and comparison with mammalian PLA2's. 817 4

Phospholipase A(2) controls the phospholipid composition in spermatozoal membranes and is released from the acrosome of human spermatozoa. The extracellular phospholipase A(2) activity of human spermatozoa was determined by matrix-assisted laser desorption and ionization time-of-flight (MALDI-TOF) mass spectrometry after destabilization of acrosome by the calcium-ionophore calcimycin. MALDI-TOF mass spectrometry allowed the monitoring of changes in both substrate and products of spermatozoal phospholipase A(2) (PLA(2)) without the use of labelled phospholipids. The spermatozoal PLA(2) was characterized as a secretory one (sPLA(2)). Secretory PLA(2) exhibited a high substrate specificity for 1-palmitoyl-2-docosahexaenoyl-sn-glycero-3-phosphocholine (PDPC), the most abundant spermatozoal phospholipid. A time- and cell number-dependent formation of the lysophospholipid PDPC was observed following incubation of extracellular medium of calcimycin-treated spermatozoa (CTS) with PDPC. Antibodies against sPLA(2), specific inhibitors of sPLA(2) and Ca(2+)-chelators could inhibit its generation. An antibody against lysophospholipase enhanced the lysoproduct concentration in the extracellular medium of CTS containing sPLA(2) because further metabolization of these products was blocked. The results demonstrated that destabilization of the acrosome is able to induce a release of secretory phospholipase A(2) from human spermatozoa with subsequent generation of lysophosphocholine in the surrounding of spermatozoa.
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PMID:Destabilization of the acrosome results in release of phospholipase A2 from human spermatozoa and subsequent formation of lysophospholipids. 1652 78

Phospholipase A2 (PLA2) enzymes play a central role in the initiation, propagation and resolution of inflammation. Here, we describe de novo expression of group IVC PLA2 (PLA2g4c) within the intestinal epithelium of Trichinella spiralis parasitised mice. This mouse mast cell protease-1 sensitive, calcium-independent PLA2 is not detectable in the jejunal epithelium of uninfected mice but becomes highly expressed within the epithelial compartment within days of nematode establishment. We propose that epithelial PLA2g4c accounts for the increased lysophospholipase activity observed during intestinal nematodiasis and that it plays a major role in the inflammatory response to nematodes.
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PMID:Trichinella spiralis induces de novo expression of group IVC phospholipase A2 in the intestinal epithelium. 1800 40


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