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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Earlier findings indicated that several other cannabinoids in addition to delta 1-tetrahydro-cannabinol (THC) were able to stimulate the synthesis of prostaglandins in cell culture systems. The present study was initiated to delineate the structural requirements for this effect within the cannabinoid series. Among the primary cannabinoids, we found that the trend was for more planar structures to show greater activity. In the case of THC metabolites, the order of activity was delta 1-THC greater than 7-oxo-delta 1, 6-THC greater than 7-OH-delta 1-THC greater than 3"-OH-delta 1-THC = 6 beta-OH-delta 1-THC = 6 alpha-OH-delta 1-THC greater than delta 1, 6-THC-7-oic acid. The latter sequence compares favorably with the available data on the behavioral assay in the rhesus monkey and the subjective "high" in humans. We also observed a good correlation between the release of arachidonic acid and the production of prostaglandin E, over a series of eight cannabinoids. This gives further support that the site of action in this effect is the elevation of activity of the phospholipase(s) responsible for supplying precursor arachidonic acid for prostaglandin synthesis.
Mol Pharmacol 1983 Jan
PMID:Prostaglandins and cannabis. XII. The effect of cannabinoid structure on the synthesis of prostaglandins by human lung fibroblasts. 686 95

Phospholipase A2 is a calcium-dependent enzyme which produces membrane fusogens. The possibility that it may be involved in exocytosis of catecholamine from primary dissociated cultures of bovine adrenal medullary cells was investigated by studying the effects on catecholamine secretion and 44Ca2+ uptake of three phospholipase A2 inhibitors: p-bromophenacyl bromide (BPB), Upjohn Compound 1002, and mepacrine. The three compounds completely inhibited catecholamine secretion induced by the nicotinic agonist 1,1-dimethyl-4-phenylpiperazinium (DMPP), elevated K+, and Ba2+. The inhibition of nicotinic agonist-induced secretion by mepacrine may have been caused by direct nicotinic antagonist activity of the drug. The phospholipase inhibitors also inhibited 45Ca2+ uptake into the cells stimulated by DMPP and elevated K+. Inhibition of 45Ca2+ uptake and catecholamine secretion exhibited identical dose-response curves. Other effects of the inhibitors were also investigated. Compound 1002 had no effect on 45Ca2+ efflux from the cells in the presence of either normal or reduced Na+ concentrations. BPB inhibited DMPP-stimulated phosphorylation of tyrosine hydroxylase which, like exocytosis, is dependent on a rise in cytosolic Ca2+. The data suggest that phospholipase A2 inhibitors block catecholamine secretion from intact chromaffin cells by blocking Ca2+ influx.
Mol Pharmacol 1983 May
PMID:Phospholipase A2 inhibitors block catecholamine secretion and calcium uptake in cultured bovine adrenal medullary cells. 686 4

The major proteins of yellowjacket venoms have been isolated and characterized immuno-chemically. They consist of hyaluronidase, phospholipase, and antigen 5. Venoms from three species of yellowjacket were studied. Vespula germanica, V. maculifrons, and V. vulgaris. The phospholipases could be isolated in good yield only when affinity chromatography was used to minimize limited proteolysis. A kallikrein-like peptidase was found present in the yellowjacket venom. Phospholipases from these three species were immunochemically indistinguishable from each other, as were their antigen 5s. Sera from individuals sensitive to yellowjacket venom contained IgE and IgG specific for antigen 5 and phospholipase.
Mol Immunol 1983 Mar
PMID:Immunochemical studies of yellowjacket venom proteins. 686 52

The membrane attack complex of human complement and its highly purified precursor proteins have been analyzed for phospholipase activity. Using three different sensitive assays, phospholipase A1, A2, C or D activity could not be detected. Based on the sensitivity of the assays employed, these results indicate the complement-mediated membrane damage is not enhanced by covalent breakdown of membrane phospholipids, but is entirely caused by physical action of the membrane attack complex. The results also imply that the putative serine esterase sites of C6 and C7 are not acting on phospholipids.
Mol Immunol 1983 Apr
PMID:The membrane attack complex of complement and its precursor proteins lack phospholipase activity. 686 55

The previously published three-dimensional structure of porcine pancreatic prophospholipase A2 at 3 A resolution was found to be incompatible with the structures of bovine phospholipase A2 and bovine prophospholipase A2. This was unexpected because of the very homologous amino acid sequences of these enzymes. Therefore, the crystal structure of the porcine enzyme was redetermined using molecular replacement methods with bovine phospholipase as the parent model. The structure was crystallographically refined at 2.6 A resolution by fast Fourier transform and restrained least-squares procedures to an R-factor of 0.241. The crystals appeared to contain phospholipase A2 and not prophospholipase A2. Apparently the protein is slowly converted under the crystallization conditions employed. Our investigation shows that, in contrast to the previous report, the three-dimensional structure of porcine phospholipase A2 is very similar to that of bovine phospholipase A2, including the active site. Smaller differences were observed in some residues involved in the binding of aggregated substrates. However, an appreciable conformational difference is in the loop 59 to 70, where a single substitution at position 63 (bovine Val leads to porcine Phe) causes a complete rearrangement of the peptide chain. In addition to the calcium ion in the active site, a second calcium ion is present in the crystals; this is located on a crystallographic 2-fold axis and stabilizes the interaction between two neighbouring molecules.
J Mol Biol 1983 Jul 25
PMID:Structure of porcine pancreatic phospholipase A2 at 2.6 A resolution and comparison with bovine phospholipase A2. 687 74

Four species of trypanosome were examined for phospholipase activities using 1-[3H]palmitoyl-2-acyl-sn-glycero-3-phosphocholine and 1-acyl-2[14C]linoleoyl-sn-glycero-3-phosphocholine as substrates. The major activity in each species is a phospholipase A1 (EC 3.1.1.32) which does not require calcium. The most effective of the detergents tested for activation of the enzyme from each species, and the Ph optima, are as follows: Trypanosoma brucei, 0.125% Triton X-100 at pH 6.0-8.5; T. congolense, 0.5 mM linoleate at pH 6.0; T. theileri, 0.1% Triton X-100 at pH 6.75; T. lewisi, 0.2 mM sodium dodecyl sulfate at pH 5.2. The specific activity of the enzyme from a pathogenic species, T. brucei, is very high (145 nmol/min/mg/protein) and could contribute to the tissue damage characteristically caused by this parasite. The level in T. lewisi, a non-pathogenic species, is relatively low (1 nmol/min/mg). The levels in T. theileri (31 nmol/min/mg) and T. congolense (10 nmol/min/mg are intermediate. These results are compatible with the hypothesis that phospholipases contribute to the pathogenicity of trypanosomes.
Mol Biochem Parasitol 1981 Feb
PMID:The phospholipases of pathogenic and non-pathogenic Trypanosoma species. 701 15

Phospholipase from Trypanosoma brucei bloodstream forms was characterized and subsequently localized. The enzyme had a specific activity of 100 nmol . min-1 . mg-1 protein. The major portion (greater than 90%) was a soluble phospholipase A1 with a pH optimum around 6; the remainder, also phospholipase A1, was particle-bound and had an optimal activity around pH 5.2. Both enzymes were maximally activated by 0.2% Triton X-100 but differed in their sensitivity towards the inhibitory action of higher concentrations of this detergent and diisopropyl fluorophosphate, the particle-bound activity being more sensitive than the soluble one. Cell fractionation showed that the particle-bound, more acidic phospholipase A1 was associated with alpha-mannosidase- and acid proteinase-containing lysosomes. Cultured procyclic trypomastigotes also contained phospholipase A but its specific activity was only 15% of that of bloodstream forms. This drastic reduction in overall activity upon transformation from bloodstream to culture form was the result of a decrease in soluble phospholipase, whereas the lysosomal activity essentially remained unchanged.
Mol Biochem Parasitol 1982 May
PMID:The phospholipases of Trypanosoma brucei bloodstream forms and cultured procyclics. 709 6

Enzyme-substrate interaction of phospholipase A2 (Naja naja oxiana) with phospholipids has been studied. Spin-labeled palmitic and stearic acids, 1-O-spin-labeled acyl-, 2-O-spin-labeled acylphosphatidyl choline and spin-labeled phosphatidyl-myo-inositol were used for this purpose. This method did not reveal hydrofobic fat-protein interaction. Phospholipase interacts only with the near lipid monolayer of liposomes and vesicles. Being formed lysophosphatidyl choline and fat acids lead to destruction of vesicles, but phospholipase renders stabilization effect.
Mol Biol (Mosk)
PMID:[Phospholipase spin-labeled phospholipids interactions]. 740 3

The esg locus is required for the formation of multicellular fruiting bodies and spores by the developmental bacterium Myxococcus xanthus. Studies have suggested that esg mutants are defective in the production of an essential signal (E-signal) used in cell-cell communication and that E-signalling is required for the expression of many developmental genes. Recently we have determined that the esg locus encodes components of a branched-chain keto acid dehydrogenase, a multienzyme complex involved in branched-chain amino acid metabolism in many bacteria and higher organisms. During vegetative growth in M. xanthus, this enzyme complex appears to participate in the production of the branched-chain fatty acids found in this organism. M. xanthus fatty acids (including the branched-chain fatty acids) have been observed to have a variety of effects on developing cells. These effects include: (i) the lysis of M. xanthus cells (autocide activity), (ii) acceleration of the rate of sporulation and (iii) rescue of sporulation by certain development-defective mutants. These and other results suggest a model in which the branched-chain fatty acids, synthesized during growth, are released from cellular phospholipid by a developmentally regulated phospholipase during fruiting-body formation. This model proposes that one or more of the branched-chain fatty acids that are released constitutes the E-signal which must be transmitted between cells to complete M. xanthus development.
Mol Microbiol 1995 Apr
PMID:Branched-chain fatty acids: the case for a novel form of cell-cell signalling during Myxococcus xanthus development. 756 80

The synthesis and evaluation of a non-radioactive hybridization probe is described, specific detecting the Clostridium perfringens alphatoxin gene (plc) by colony blot hybridization assay. A vector free digoxigenin-dUTP-labelled probe was generated by polymerase chain reaction (PCR) targeting the cloned plc gene of C.perfringens strain ATCC 13124. In a colony blot hybridization assay 296 strains of C.perfringens were tested for plc. None of the strains failed in hybridization. Presence of plc was even demonstrated in C.perfringens strains reported to lack lecithinase activity. Specificity of the probe was shown with various strains of other bacterial species. None different Clostridia sp. tested, e.g. C.bifermentans, C.tertium, C.novyi, C.chauvoei, C.sporogenes, C.difficile, C.putrifucum, C.sordellii, C.botulinum, C. septicum and C.histolyticum, hybridized with the plc specific probe. Strains expressing an enzymatically related phospholipase like Bacillus cereus, Listeria monocytogenes and Staphylococcus aureus gave also negative results. Comparing the results of conventionally used egg yolk turbidity assay and those gained with DNA hybridization, the plc probe proved to be a much more sensitive and specific diagnostic tool for the detection of C.perfringens plc.
Mol Cell Probes 1995 Apr
PMID:Synthesis and evaluation of a non-radioactive gene probe for the detection of C.perfringens alpha toxin. 760 69


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