Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.4.3 (phospholipase C)
 18,461 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Lipopolysaccharide (LPS) preparations from the Bacteroides species B. endodontalis, B. intermedius, B. denticola, and B. melaninogenicus and from Fusobacterium nucleatum, Haemophilus actinomycetemcomitans, Capnocytophaga gingivalis, and Eikenella corrodens directly agglutinated erythrocytes of some kinds of animals. LPSs from the Bacteroides species B. gingivalis, B. asaccharolyticus, B. corporis, and B. loescheii and from Capnocytophaga ochracea did not possess any hemagglutinating activity. Pretreatment of LPSs with lipase and phospholipase C completely eliminated the hemagglutinating activity. The hemagglutinating activity was also affected by human serum, saliva, colistin, and polymyxin B but was not affected by sugars, amino acids, EDTA, or proteolytic enzymes. The role of this hemagglutinating activity in colonization by these microorganisms of the periodontal region is discussed.
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PMID:Hemagglutinating activity of lipopolysaccharides from subgingival plaque bacteria. 367 48

Using a commercially available test for LDL cholesterol (Boehringer Mannheim), a method was developed for determination of LDL apolipoprotein B without using ultracentrifugation. The infranatant obtained by precipitation of serum with polyvinylsulphate was redissolved in a saline citrate solution and incubated with phospholipase A2, phospholipase C, phospholipase D or triglyceride lipase, respectively. When the saline-citrate redissolved precipitate was monitored by electron microscopy, it appeared as a fibriform network. The additional incubation with phospholipase A2, C, D, or triglyceride lipase resulted in a molecularization of LDL particles. By electron microscopy these particles could not be distinguished from LDL particles isolated by ultracentrifugation. In radial immunodiffusion tests, the additional incubation of the redissolved precipitate with phospholipase C or phospholipase D resulted in a total loss of the slight immunoreactivity observed before phospholipase incubation. However, additional incubation with triglyceride lipase resulted in a significant increase in immunoreactivity. Only the additional incubation of the redissolved precipitate with phospholipase A2 resulted in an immunoprecipitation reaction comparable to that with LDL particles isolated by ultracentrifugation. Using a resolubilized and phospholipase A2-incubated precipitate of a pool serum as apolipoprotein B standard, a good correlation was obtained between apolipoprotein B values measured in this dissolved precipitate and those measured in the d greater than 1.006 kg/l fraction isolated by ultracentrifugation (r = 0.95; y = 0.95x + 0.018; n = 44).
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PMID:Apolipoprotein B determination in the dissolved precipitate obtained after precipitation of LDL with polyvinylsulphate. An alternative method for the determination of LDL apolipoprotein B without using ultracentrifugation. 373 4

The variant surface glycoprotein (VSG) of Trypanosoma brucei has a glycolipid covalently attached to its C terminus. This glycolipid, which anchors the protein to the cell membrane, is attached to the VSG polypeptide within 1 min after translation (Bangs, J. D. Hereld, D., Krakow, J.L., Hart, G. W., and Englund, P. T. (1985) Proc. Natl. Acad. Sci. U. S. A. 82, 3207-3211). This rapid processing suggests that, prior to incorporation, the glycolipid may exist in the cell as a preformed precursor which is transferred to the VSG polypeptide en bloc. We have isolated a molecule which has properties consistent with it being a VSG glycolipid precursor. It is highly polar and can be labeled by [3H] myristate but not by [3H]palmitate. It reaches steady state during continuous labeling with [3H]myristate and shows rapid turnover in pulse-chase experiments, suggesting that it is a metabolic intermediate rather than an end product. When treated with HNO2 it liberates phosphatidylinositol, as does VSG (Ferguson, M. A. J., Low, M. G., and Cross, G. A. M. (1985) J. Biol. Chem. 260, 14547-14555). Also, like VSG, it releases a compound which co-migrates on thin layer chromatography with dimyristylglycerol when treated with the purified endogenous phospholipase C from trypanosomes. After treatment with this lipase, the putative precursor can be immunoprecipitated by antibodies directed against the C-terminal cross-reactive antigenic determinant of the VSG. These data provide strong evidence that this glycolipid is a VSG precursor.
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PMID:Identification of a glycolipid precursor of the Trypanosoma brucei variant surface glycoprotein. 374 82

The surface coat of Trypanosoma brucei is composed of 10(7) molecules of the variant surface glycoprotein (VSG). Each VSG molecule is tethered to the cell membrane by a glycolipid moiety which contains 1,2-dimyristoyl-sn-phosphatidylinositol (Ferguson, M. A. J., Low, M. G., and Cross, G. A. M. (1985) J. Biol. Chem. 260, 14547-14555). Following cell lysis, an endogenous phospholipase C cleaves dimyristoyl glycerol from the glycolipid, releasing soluble VSG. We have purified this enzyme, which we designate VSG lipase, by detergent extraction, (NH4)2SO4 fractionation, hydrophobic chromatography, and cation exchange chromatography. It is purified 2600-fold and is virtually homogeneous. Based on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the apparent molecular mass is 37 kDa. In solutions containing the detergent 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonic acid (CHAPS), the Stokes radius (2.6 nm), S20,w (3.7 S), and v (0.77 cm3/g) of VSG lipase suggest a molecular mass for the native enzyme of about 47 kDa, part of which may be due to bound CHAPS. Therefore, it is probably monomeric. VSG lipase does not require Ca2+; it is stimulated by chelating agents or dithiothreitol, and it is inhibited by some sulfhydryl reagents. The purified enzyme appears to be highly specific. Under the conditions of our assay, it cleaves the VSG glycolipid, a biosynthetic precursor of the VSG glycolipid, and, to a much lesser extent, 1,2-dimyristoyl-sn-phosphatidylinositol. There was no apparent cleavage of other myristate-containing lipids of trypanosomes or 1-stearoyl-2-arachidonoyl-sn-phosphatidylinositol.
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PMID:A phospholipase C from Trypanosoma brucei which selectively cleaves the glycolipid on the variant surface glycoprotein. 375 91

In order to determine the influence of plasma lipids on the apparent molecular size of human F VIII/vWF and on the relationship of the factor-related properties, namely F VIII:C, F VIIIR:Rcof, and F VIIIR:Ag to F VIII/vWF, the factor's elution pattern in the presence of lipids on Sephacryl 1000 was investigated. When fresh plasma of fasting donors was chromatographed on this gel, F VIII/vWF eluted in a single sharp peak with all three F VIII-related activities appearing in the separation range of the gel column. When fresh postprandial lipaemic plasma was chromatographed on this gel, F VIII/vWF showed distinct heterogeneity in the elution pattern with respect to molecular size and relationship to the F VIII-related properties. After incubation of lipaemic plasma with phospholipase C the elution pattern of F VIII/vWF changed from heterogeneity to homogeneity similar to those of plasma of fasting donors. After incubation of lipaemic plasma with triglycerid lipase the elution pattern of F VIII/vWF remained heterogenous. A similar heterogeneity in the elution pattern of F VIII/vWF was found when plasma of fasting donors was mixed with a preparation of very low density lipoproteins derived from human postprandial plasma or with a preparation of coagulant-active phospholipids.
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PMID:Heterogeneity of human factor VIII/vWF in lipaemic plasma. 392 7

It has been well recognized that acyl groups of phospholipids play an important role for structure and function of biomembrane. The turnover of these acyl groups in normal brain biomembrane is also well known. Some types of enzymic system related to this turnover has been investigated. Phospholipase A, PI-specific phospholipase C, lipase, lysophospholipase and acylCoA: lysophospholipid acyltransferase belong to these enzymic systems. In this report, the sequential changes of phospholipase A, PI-specific phospholipase C, lipase, lysophospholipase and acylCoA: lysophospholipid acyltransferase activities in ischemic rat brain were examined. The purpose of this study was to examine the enzymic changes of deacylation-reacylation cycle of biomembrane phospholipid in ischemic brain. Ischemic brain were produced by decapitation and activities of 5 enzymes were assayed in microsomal fraction. The activities of phospholipase A, PI-specific phospholipase C, lipase showed high value during early stage of ischemia for 15 or 30 min and then decreased gradually. Lysophospholipase activity was not changed for 120 min. On the other hand, acylCoA: lysophospholipid acyltransferase activity showed gradual decrease from the beginning of ischemia. There are some reports that in early ischemic stage, the concent of free fatty acids increase, while that of phospholipid decrease. The present results may suggest that the changes of free fatty acid and phospholipid in ischemic brain are related to these enzymic system.
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PMID:[The activities of phospholipase A, PI-specific phospholipase C, lipase, lysophospholipase and acylCoA: lysophospholipid acyltransferase in ischemic brain microsomal fraction]. 402 86

Non-competitive inhibition of snake venom phospholipase A2 which has been exhibited by bovine plasma phospholipase A inhibitor, a kind of lipoprotein, was not observed unless the inhibitor was preincubated with the enzyme. The inhibition seemed to be due to the formation of the enzyme-inhibitor complex, which was identified by immunoelectrophoresis. The enzyme-inhibitor interaction was observed maximally on incubation at physiological pH, but not below pH 5. The inhibitor was inactivated by trypsin digestion and heat treatment. It suppressed the phospholipase A2 activities of rat blood plasma as well as of the snake venom and porcine pancreas, but not the enzyme activities such as those of phospholipase C of Bacillus cereus, lipase of porcine pancreas, trypsin, and papain. The inhibitor also showed the ability to decrease membrane-bound phospholipase A1 and A2 activities in intracellular organelles such as plasma membranes, mitochondria, lysosomes, and microsomes. In view of these facts, it was concluded that the plasma inhibitor is specific for phospholipase A.
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PMID:Studies on phospholipase A inhibitor in blood plasma. II. Interaction of phospholipase A inhibitor with phospholipase A and its specificity. 404 47

Australia antigen [Au(1)], a particle associated with viral hepatitis, was isolated from the plasma of a patient with chronic anicteric hepatitis and leukemia who had received radioactive phosphorus. We have found that the immunoreactivity and appearance of Au(1) in the electron microscope were not altered by treatment with enzymes including trypsin, pronase, lipase, phospholipase C, ribonuclease, deoxyribonuclease, amylase, and neuraminidase. In contrast, other serum constituents were degraded by these enzymes. Therefore, treatment of the patient's plasma with many enzymes was exploited as an initial step for the isolation of Au(1). Subsequently, Au(1) was purified from the enzyme-treated (32)P-labeled plasma by gel filtration through Sephadex G-200 and centrifugation through sucrose and in cesium chloride gradients. There were no detectable human serum components in the purest fractions, as tested by immunoelectrophoresis and immunodiffusion. The density of the purified Au(1) was 1.21 in CsCl. The particle measured about 200 A in diameter, was predominantly spherical in shape and appeared to be composed of subunits. Nucleic acids were not detected by spectrophotometric, radiochemical, and chemical analyses. Immunoreactivity of purified Au(1) was destroyed by heating for 1 hr at 85 degrees C but was stable at 56 degrees C. Treatment with Carnoy's solution (3 parts ethanol:1 part glacial acetic acid) followed by pronase disrupted the particles as seen with the electron microscope. These findings, combined with other published information on Australia antigen and viral hepatitis, suggest that the bulk of Australia antigen in the blood of this patient is an incomplete virus or virus capsid.
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PMID:Australia antigen (a hepatitis-associated antigen): purification and physical properties. 424 40

Cell envelopes of Chromobacterium violaceum were isolated and treated under controlled conditions with trypsin, Pronase, lipase, phospholipase C, lysozyme, and a mixture of enzymes produced by a bacteriolytic Pseudomonas sp. After each enzyme treatment, losses in dry weight, protein, lipid, carbohydrate, 2,6-diaminopimelic acid, and total phosphorus were determined. Electron-microscopic examination of the enzyme-treated envelopes indicated complete or partial loss of envelope rigidity or some envelope fragmentation, or both. Each enzyme hydrolyzed at least one envelope component and liberated several others into the supernatant fluid, where they appeared as nondialyzable particulate components, identified by means of electron microscopy. Unlike the other enzymes, the Pseudomonas sp. enzyme mixture partially liberated all major envelope components except phosphorus, heptose, and 2-keto-3-deoxy octonic acid. In spite of these large losses, the envelopes preserved some features of their integrity and elongated shape.
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PMID:Effect of enzymes on the composition and structure of Chromobacterium violaceum cell envelopes. 577 32

Phospholipase C (EC 3.1.4.3.) from Clostridium perfringens (crude extracts) was used to study the role of phospholipids in the osmotic permeability of the urinary bladder of the toad. When added to the serosal bath (430 mU/ml) it inhibited the effects of antidiurectic hormone (ADH) and exogenous cyclic AMP. Under the same conditions the increase in osmotic flow produced by serosal hypertonicity (SH) was slightly enhanced by the lipase. The hydroosmotic effect of SH was greatly potentiated by the lipase by decreasing 10-fold the Ca2+ concentration. The SH-induced flow was inhibited by the lipase if the Ca2+ or the H+ concentration was increased 10-fold, but not if the increase in positive charges was produced by a concentration of Mg2+. Phospholipase C had no effect on the action of either ADH or SH if added to the mucosal bath. Serosal neuraminidase or phospholipase A2 could not mimic the effect of phospholipase C on SH. The effect of phospholipase C on the response to SH was not modified if fatty acid-free bovine serum albumin was added to the bath. Therefore, the release of products of lipolysis into the bath do not seem to be responsible for the effects of phospholipase C on SH-induced water flow. The results suggest that the effects of the enzyme on the composition and rearrangement of lipids at the basolateral membrane produce modifications of the water flow. Ca2+ and H+ may modify the enzyme-substrate interaction, suggesting that different phospholipids may be differentially involved in the control of water permeability of the basolateral membrane.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Ca2+- and H+-dependent effects of crude bacterial phospholipase C on the hydroosmotic response of toad urinary bladder to serosal hypertonicity. 608 40


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