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:3.1.4.3 (phospholipase C)
18,461 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Staphylococcus aureus (Wood 46) was grown aerobically and anaerobically in supplemented 3% (w/v) Tryptone Soya Broth medium for 24 h at 37 degrees C. Although the bacterial density achieved was 9 times higher in the aerobic culture, the exoprotein produced per unit of bacterial dry weight was only 1.4 times higher than in the anaerobic culture. However, the SDS-PAGE patterns of extracellular proteins were quite different: the aerobic products occurred almost exclusively in the mol. wt range 15-30000 compared with 30-60000 for those produced anaerobically. The only major component common to both preparations was alpha-toxin which accounted for 2.4 times more of the total exoprotein under aerobic than under anaerobic conditions.
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PMID:A comparison of the patterns of extracellular proteins produced by the high alpha-toxin-secreting organism Staphylococcus aureus (Wood 46) during aerobic and anaerobic growth. 398 Nov 33

An effective concentration of alpha-toxin from Staphylococcus aureus Wood 46, directly from the culture supernatant, could be achieved by adsorption on digitonin-sepharose and elution with 3 mol/l sodium thiocyanate (NaSCN). The toxin was further purified by gelchromatography. The purified product yielded 1 single protein band upon SDS-polyacrylamide electrophoresis. It was nonhemolytic, but reacted with anti-alpha-toxin under complement fixation. Dialysis against 0.14 mol/l NaCl with hydrophobic amino acids partially reactivated the alpha-hemolytic activity of the toxin. Ultracentrifugal analysis yielded sedimentation coefficients for the purified toxin of approximately 3,7 S when dissolved in 3 mol/l NaSCN and of about 12 S after dialysis against 0.14 mol/l NaCl (Table 1). The spontaneous oligomerization of the alpha-toxin during dialysis against 0.14 mol/l NaCl possibly resulted from a change in configuration induced by its adsorption to digitonin-sepharose.
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PMID:Purification of oligomeric staphylococcal alpha-toxin by affinity chromatography on digitonin-sepharose. 400 34

In cell culture, a partially purified commercial preparation of phospholipase C (PLC) from Clostridium welchii inhibited fusion of myoblasts at concentrations of 12-50 microg per ml. At lower concentrations, PLC-treated cultures were indistinguishable from controls, and at concentrations above 100 microg per ml, PLC-treated cells detached from their substrates. The effect was reversible and fusion resumed approximately one cell cycle time after removal of the enzyme. Neither the percent of cells in the mitotic cycle nor the duration of the different phases of the cycle were altered by PLC at concentrations which inhibited fusion. Cell motility was not reduced by the enzyme. Unfused, PLC-treated myoblasts were virtually indistinguishable in ultrastructure from untreated cells just before fusion. In the presence of PLC, mononucleated myogenic cells did not synthesize thick (150 A) filaments. Treatment of culture medium with insolubilized commercial PLC did not abolish the capacity of the medium to support myogenesis. Chondrocytes treated with PLC divided repeatedly but failed to synthesize metachromatic matrix and failed to incorporate labeled sulfate into chondroitin sulfate. PLC was further purified by chromatography on Sephadex G-100. The resulting preparation was free of detectable protease, yielded one band on SDS-acrylamide gel electrophoresis, and displayed all of the biological activities of the less pure material.
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PMID:Inhibition of cellular differentiation by phospholipase C. I. Effects of the enzyme on myogenesis and chondrogenesis in vitro. 435 37

Rabbit or human erythrocytes lysed with Staphylococcus aureus alpha-toxin were solubilized with Triton X-100, and the toxin was subsequently isolated by gel chromatography, sucrose density gradient centrifugation, and reincorporation into liposomes. In the presence of Triton X-100, the toxin exhibited a sedimentation coefficient of 11S and eluted at a position between those of IgG and alpha 2-macroglobulin in gel chromatography. A single polypeptide subunit of 34,000 mol wt was found in SDS PAGE. In the electron microscope, ring-shaped or cylindrical structures were observed, 8.5-10 nm in diameter, harboring central pits or channels 2-3 nm in diameter. An amphiphilic nature of these structures was evident from their capacity to bind lipid and detergent, aggregation in the absence of detergents, and low elutability from biological and artificial membranes through ionic manipulations. In contrast to the membrane-derived form of alpha-toxin, native toxin was a water-soluble, 34,000 mol wt, 3S molecule, devoid of an annular structure. Because studies on the release of radioactive markers from resealed erythrocyte ghosts indicated the presence of circumscribed lesions of approximately 3-nm effective diameter in toxin-treated membranes, the possibility is raised that native alpha-toxin oligomerizes on and in the membrane to form an amphiphilic annular complex that, through its partial embedment within the lipid bilayer, generates a discrete transmembrane channel.
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PMID:On the mechanism of membrane damage by Staphylococcus aureus alpha-toxin. 627 94

We describe here a new mutant of Pseudomonas aeruginosa PAO, strain D10C (genotype plcB), which produces phospholipase C and alkaline phosphatase constitutively. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the extracellular proteins produced by this mutant in high- and low-Pi media revealed that the mutation resulted in a marked deficiency of one major Pi-regulated protein of 41,000 molecular weight and constitutive synthesis of all other major extracellular Pi-regulated proteins. Furthermore, the plcB mutant was deficient in phosphate transport. A plcA mutation, which also led to a loss of the 41,000-molecular-weight protein, was similarly deficient in Pi transport. The genetic loci, plcA and plcB, located at 22 to 23 min on the PAO chromosome, were indistinguishable by conjugational and transductional mapping, and may therefore be in the same gene or in a cluster of genes which regulate the synthesis of Pi-repressible proteins.
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PMID:Phospholipase C regulatory mutation of Pseudomonas aeruginosa that results in constitutive synthesis of several phosphate-repressible proteins. 680 40

Rabbit TNF has been purified 2000-fold by a series of salt precipitations, gel filtrations, ion exchange chromatography, and lectin affinity chromatography to a single species on SDS-polyacrylamide gel electrophoresis (SDS-PAGE). TNF activity could be recovered from nondenaturing gel systems and has been shown to be an alpha-globulin with an isoelectric point of 5.1. The m.w. was estimated to be 68,000 d by SDS-PAGE, 55,000 by gel filtration, and 52,000 by glycerol gradient centrifugation. TNF activity was stable over the pH range of 6 to 10 and was relatively heat stable, not being inactivated at 70 degrees C for 1 hr. TNF activity was pronase sensitive, but relatively trypsin resistant. Neuraminidase and phospholipase C treatment did not destroy TNF activity. Partially purified TNF was still capable of eliciting hemorrhagic necrosis in susceptible tumors. Crude TNF serum had an interferon titer of 3000 U, whereas the partially purified sample had a titer of <30 U.
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PMID:Purification and physico-chemical characterization of rabbit tumor necrosis factor. 699 83

Nicotinic acetylcholine receptor (AcChR) was purified from fetal calf muscle by an affinity chromatographic method utilizing alpha-neurotoxin from Naja naja siamensis as an immobilized ligand. Preparations of AcChR with an average specific activity of 5 nmol of alpha-toxin bound/mg of protein were obtained, i.e., 75% of the theoretical specific activity assuming identity with Torpedo AcChR. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the purified AcChR consistently showed the presence of five polypeptides, having apparent Mr's of 42 000, 44 000, 49 000, 55 000, and 58 000, respectively. The peptide of Mr 44K was demonstrated to be actin. The amino acid composition of fetal calf AcChR was shown to be similar to that of Torpedo AcChR. In addition, calf AcChR contained large amounts of amino sugars. The sedimentation coefficient of the purified calf AcChR was found to be 9.25 +/- 0.25, i.e., similar to the monomeric form of electric organ AcChR. Determination of the isoelectric point of alpha-bungarotoxin/calf AcChR complexes revealed the presence of two charged forms, having pI values of 5.16 +/- 0.13 and 6.05 +/- 0.18, respectively.
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PMID:Mammalian muscle acetylcholine receptor purification and characterization. 710 16

Human E express two surface forms of decay-accelerating factor (DAF; CD55). On SDS-PAGE under reducing conditions the major form, DAF-1, migrates as a 70-kDa protein and the minor form, DAF-2, present at < 10% the amount of DAF-1, migrates as a 140-kDa protein (Kinoshita, T., S. I. Rosenfeld, and V. Nussenzweig. 1987. J. Immunol. 138:2994). Both forms possess decay-accelerating activity and, after purification from solubilized E, reinsert into sheep E, indicating a glycosylphosphatidylinositol anchor. In contrast to human cells, these two forms of DAF from orangutan E are expressed in approximately equal amounts (Nickells, M. W., and J. P. Atkinson. 1990. J. Immunol. 144:4262). An orangutan B lymphocyte cell line, CP81, also expresses similar quantities of both forms. These sources of orangutan DAF were utilized for further characterization of DAF-2. Orangutan and human DAF-1 were 98% and 95% homologous at the nucleotide and amino acid levels, respectively. Northern and Southern analyses of orangutan DAF were also similar to those for human DAF. Tryptic peptide maps of DAF-1 and DAF-2 were identical. After treatment with phosphatidylinositol-specific phospholipase C and glycosidases, the change in M(r) of DAF-2 was consistent with it possessing two glycosylphosphatidylinositol anchors and twice as much oligosaccharide as DAF-1. Biosynthetic analysis demonstrated a single 46-kDa precursor for both forms. Taken together, these data indicate that DAF-2 is a covalently cross-linked dimer of DAF-1. Analysis of a series of human DAF deletion mutants localized the cross-link(s) within the short consensus repeat domains.
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PMID:Characterization of DAF-2, a high molecular weight form of decay-accelerating factor (DAF; CD55), as a covalently cross-linked dimer of DAF-1. 750 31

MCA44 is a mAb with the capacity to sensitize neuraminidase-treated guinea pig E for hemolysis by homologous guinea pig C, and the Fab fragments of this mAb could also sensitize guinea pig E interfering with the function of a membrane inhibitor of C on guinea pig E. Using an immunosorbent column to which MCA44 was coupled, the antigenic molecule termed 44Ag was purified from the glycoprotein fraction extracted from E membranes. C intermediate sheep E treated with guinea pig C1 and C4 after sensitization with Ab (EAC14b cells) lost the ability to generate C3 convertase with C2 after incubation with 44Ag. Treatment of guinea pig E and PBL with phosphatidyl-inositol specific phospholipase C (PIPLC) partially removed 44Ag, as determined by flow cytometric analysis after immunofluorescence staining with MCA44. However, 125I-labeled 44Ag adsorbed to human E was efficiently removed by PIPLC treatment with a slight reduction in M(r). The 44Ag purified on an immunosorbent column showed three bands on SDS-PAGE. However, partial N-terminal amino acid sequences of the 55-kDa, 70-kDa, and 88-kDa bands under nonreducing conditions were identical and the sequence was 55% homologous to the N-terminal sequence of human decay accelerating factor (CD55). Intracutaneous administration of MCA44 or its F(ab')2 fragment resulted in increased capillary permeability, even after 3 days, as determined by the appearance of Evans blue spots after i.v. administration of the dye. Because control Abs including anti-class I-MHC did not cause such increased capillary permeability, the increase in permeability caused by MCA44 was likely induced by blocking the function of 44Ag in vivo, indicating a crucial role for these molecules in preventing over-activation of C at the site.
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PMID:A monoclonal antibody that blocks the complement regulatory activity of guinea pig erythrocytes and characterization of the antigen involved as guinea pig decay-accelerating factor. 753 42

Immunohistochemical and/or indirect immunofluorescence analysis with monoclonal antibody (MAb) H19 demonstrated the expression of protectin (CD59) in 54 surgically removed metastatic melanoma lesions and on 8 out of 12 melanoma cell lines. CD59 expression had a low degree of intra- and intertumor heterogeneity. SDS-PAGE analysis showed that the molecular weight of CD59 expressed on melanoma cells is about 20 kDa. Treatment of melanoma cells with 5U/ml of phosphatidylinositol-specific phospholipase C completely abolished cell-surface expression of CD59. Interferon-gamma and/or tumor necrosis factor-alpha or phorbol 12-myristate 13-acetate neither modulated the expression of CD59 by melanoma cells nor influenced the amounts of CD59-specific mRNA. F(ab')2 fragments of anti-CD59 MAb YTH53. I did not inhibit the lysis of melanoma cells by allogeneic natural killer (NK) cells or lymphokine-activated killer (LAK) cells. In contrast, the whole Ig molecule of MAb HI9 or YTH53.I significantly (p < 0.05) enhanced NK-cell-mediated lysis of melanoma cells, suggesting the induction of antibody-dependent cell-mediated cytotoxicity. Lastly, masking of CD59 by MAb YTH53.I or its F(ab')2 fragments significantly (p < 0.05) enhanced, in a dose-dependent fashion, the lysis of anti-GD3-sensitized melanoma cells by homologous complement. These data demonstrate that CD59 expressed by human melanoma cells might regulate host-tumor interaction by protecting neoplastic cells from complement-mediated lysis.
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PMID:Expression of protectin (CD59) in human melanoma and its functional role in cell- and complement-mediated cytotoxicity. 753 80


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