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)

A group of proteins was readily extracted at neutrality from trichloroacetic acid precipitates of staphylococcal culture filtrate supernatants, while alpha-toxin was dissolved and activated by treating the precipitate with 8 M urea, with acidic buffers or by heating to 90-100 degrees C at neutrality. Heat activation of the precipitate produced a relatively pure alpha-toxin with a molecular weight of 39,000. alpha-Toxin was eluted together with three other proteins on hydroxyl apatite chromatography, and evidence was obtained for an association between the four proteins. On isoelectric focusing a haemolytic fraction was obtained at pH 6.2, probably due to acid activation of the precipitate formed at the cathodic end of the column. The alpha-haemolytic fractions with pI's of 7.4 and 8.6 were shown to consist of alpha-toxin only when analyzed by acrylamide electrophoresis in the presence of sodium dodecyl sulphate. The haemolytic component with a pI of 9.2 contained two additional components of molecular weights of 27,500 and 18,000. Chromatography of this material on Sephadex G-200 showed that alpha-toxin and the two proteins appeared as a high molecular complex.
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PMID:Multiple forms of staphylococcal alpha-toxin. 0 Aug 86

1. Phospholipase C [EC 3.1.4.3] found in the growth medium of Streptomyces hachijoensis was purified about sixty-fold by dialysis and column chromatography on Sephadex G-50. 2. The active fraction was separated by isoelectric focusing into two fractions, phospholipase C-I (pI 6.0) and phospholipase C-II (pI 5.6). 3. Both purified phospholipases C were homogeneous by immunodiffusion and were not differentiated as regards antigencity. 4. Phospholipase C-I had maximal activity at pH 8.0 and the optimal temperature was 50degree. Phospholipase C-I was stable at 50degrees for 30 min and was stable at neutral pH. 5. The activity of phospholipase C-I was inhibited by high concentrations of various detergents such as Triton X-100, sodium, cholate, SDS and was also inhibited by Ca2+, Ba2+, Al3+, and EDTA, but was stimulated by Mg2+, and ethyl ether. 6. The Km value of phospholipase C-I was 0.9 mM, using phosphatidylcholine as a substrate. 7. By the gel filtration procedure, the molecular weights of phospholipase C-I and -II were both determined to be 18,000. 8. Phosphatidylcholine, phosphatidylinositol, cardiolipin, sphingomyelin, and lysophosphatidylcholine were hydrolyzed by phospholipase C-I, but phosphatidylethanolamine and phosphatidylserine were hydrolyzed with difficulty under the same conditions, Phospholipase C-I also hydrolyzed phosphatidic acid.
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PMID:Studies on phospholipases from Streptomyces. III. Purification and properties of Streptomyces hachijoensis phospholipase C. 0 11

The latency of inosine-5'-diphosphatase has been studied in microsomes isolated from rat liver. The appearance of latent activity was the result of an increase in the Vmax of the enzyme. This was observed when assays were carried out in the presence of sodium deoxycholate, after microsomes were treated wtih phospholipase C, or at pH 10.3 and after microsomes were subjected to nitrogen cavitation. The apparent Km of inosine-5'-diphosphatase for IDP was unchanged when microsomes were treated with phospholipase C or at pH 10.3 after both these treatments approximately 85% of the enzyme remained bound to the membrane. In contrast, when microsomes were treated with phospholipase C or at pH 10.3 after both these treatments approximately 85% of the enzyme remained bound to the membrane. In contrast, when microsomes were treated with sodium deoxycholate or subjected to nitrogen cavitation, approximately 75% of the inosine-5'-diphosphatase activity was released from the membrane, and the apparent Km of the enzyme for IDP increased 4- and 2-fold, respectively. Microsomal cisternae were loaded with lead phosphate by incubation with glucose-6-P and Pb2+, and the release of this lead phosphate following the addition of EDTA to the medium was determined to estimate the permeability of the microsomal membrane. When microsomes were treated with sodium deoxycholate, phospholipase C, or at alkaline pH, the microsomal membrane became almost completely permeable to EDTA under conditions where there was little or no increase in the activity of inosine-5'-diphosphatase. Microsomes were treated at pH 10.3 and then adjusted slowly to pH 7.5. The activity of inosine-5'-diphosphatase decreased to the same activity observed in untreated preparations. The results seem of exclude the possibility that latent inosine-5'-diphosphatase activity is the result of an increased permeability of the membrane to IDP. They are, however, consistent with the presence of a noncompetitive inhibitor of the enzyme in the microsomal membrane.
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PMID:Latency of inosine-5'-diphosphatase in microsomes isolated from rat liver. 1 80

The effects of a variety of agents on guanylate cyclase activity were tested in broken cell preparations of mammary glands from midpregnant mice. Of the agents tested, only phospholipase A, triton X-100, and an impure egg lysolecithin preparation enhanced the activity of guanylate cyclase in mammary gland homogenates; other agents, including sodium azide and phospholipase C, and purified egg lysolecithin had no effect. Phospholipase A increased the activity of guanylate cyclase in the 150,000 g pellet fractions of mammary gland homogenates, bud did not consistently enhance guanylate cyclase in the 150,000 g supernatant fractions. Phospholipase A did not appear to enhance guanylate cyclase activity by solublizing the enzyme from the 150,000 g pellet. Triton X-100, in contrast, appeared to act by solubilizing guanylate cyclase from the material present in the 150,000 g pellet. Triton X-100 increased by several fold guanylate cyclase activity in the tissue homogenates and the 150,000 g pellets, but did not consistently enhance enzyme activity in the 150,000 g supernatant. Triton X-100 had no effect on the apparent Km of guanylate cyclase.
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PMID:Effects of phospholipase A and triton x-100 on guanylate cyclase activity in mammary gland homogenates from mice. 2 72

After alkaline extraction, purified subsynaptic fragments isolated from Torpedo electric tissue exhibit on sodium dodecyl sulfate/polyacrylamide gel electrophoresis predominant peptides of apparent Mr 41,000, 50,000, and 65,000 (i.e., the peptides characteristic of the nicotinic receptor purified and isolated in detergent solutions). The peptide of Mr 43,000 that is also found in the isolated postsynaptic membranes is recovered in the supernatant after alkaline extraction. The alkaline-extracted membranes were functionally intact, as demonstrated by the following criteria. The kinetics of binding of [3H]acetylcholine in the presence and absence of 30 micron carbamoylcholine to occupy acetylcholine binding sites, [14C]-meproadifen [2-(diethylmethylaminoethyl)-2,2-diphenylvalerate iodide ] was bound with a dissociation constant, KD, of 0.3 +/- 0.1 micron to 0.3 +/- 0.1 site per [3H]alpha-toxin site. This binding was displaced by perhydrohistrionicotoxin. The carbamoylcholine-stimulated efflux of 22Na+ from the Torpedo vesicles were preserved after alkaline extraction. It is concluded that not only the acetylcholine binding site, but also the local anesthetic binding site, must be associated with the peptides of the cholinergic receptor itself and not that of Mr 43,000. Those peptides remaining after alkaline extraction are also sufficient for permeability control.
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PMID:Acetylcholine and local anesthetic binding to Torpedo nicotinic postsynaptic membranes after removal of nonreceptor peptides. 3 54

The ultrastructural study of liver tissues from 38 patients with type B viral hepatitis consistently showed the presence of hepatitis B core antigen of 21-25 nm size in the liver cell nuclei and to a lesser extent in the cytoplasm. This finding and the demonstration of the tubular form of hepatitis B surface antigen in the proliferative degranulated endoplasmic reticulum constituted the etiologic criterion for the diagnosis of the disease. The double-shelled Dane-like particles were frequently found in association with the tubular form of the surface antigen. The core particles were found in the protoplasmic processes of hepatocytes and this correlated with the immunofluorescent microscopic findings that the antigen may be shed into circulation with the protoplasm. The core antigen was found to resist digestion by various enzymes such as protease, DNase, RNase, phospholipase C, lipase, lysozyme, diastase, neuraminidase and hyaluronidase, all of which did not destroy the immunoreactivity as demonstrated by immunoelectron and immunofluorescent microscopy. Similarly, sodium dodecyl sulfate, Tween 80 and mercaptoethanol also had no effect. The formalin-fixed paraffin-embedded liver tissue sections could be treated with protease to facilitate the immunofluorescent staining for the core antigen in tissue.
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PMID:Structural and immunoreactive characteristics of hepatitis B core antigen. 5 6

Subviral cores have been prepared from the oncornavirus-like particle found in human milks with the use of phospholipase C and ether or Sterox SL. The major protein of these cores has a molecular weight of 27,000 daltons, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. This protein is found in the core fractions of reverse transcriptase-positive milks and is absent in negative milks. It is distributed in sucrose gradients only in those fractions containing cores and reverse transcriptase activity. The major core protein of the human milk oncornavirus-like particle is electrophoretically identical to the major core protein of the mouse mammary tumor virus.
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PMID:Identification and isolation of the major core protein from the oncornavirus-like particle in human milk. 6 99

Phospholipase C (phosphatidylcholine choline-phosphohydrolase, EC 3.1.4.E) from Bacillus cereus (IAM-1208) was adsorbed to palmitoyl cellulose from a crude enzyme solution at pH 5--9. The adsorption was not influenced by ionic strength up to 2 M NaCl. The adsorbed enzyme was eluted almost completely by washing the cellulose with a suitable detergent, such as Triton X-100, Adekatol SO-120, Cation DT-205, or sodium deoxycholate. The enzyme was then purified by column chromatography on a palmitoylated textile (palmitoylated gauze) with an overall recovery of 91% and a 467-fold increase in specific activity over that of enzyme in the crude culture supernatant. Subsequent fractionation with acetone and chromatography on a Sephadex G-75 column separated two nearly homogeneous phospholipase C's. The enzyme adsorbed on palmitoyl cellulose was active, although its activity was about one-fourth that of free phospholipase C. Therefore, the enzyme appeared to be adsorbed to the cellulose through a hydrophobic site that was distinct from the catalytic site on the enzyme molecule.
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PMID:Purification of phospholipase C from Bacillus cereus by hydrophobic chromatography on palmitoyl cellulose. 11 Aug 96

The conditions necessary for the secretion of phospholipase C (phosphatidylcholine cholinephosphohydrolase) by Pseudomonas aeruginosa were studied. Enzyme secretion by washed cell suspensions required a carbon source and ammonium, potassium, and calcium ions. The calcium requirement could be substituted by magnesium and strontium but not by copper, manganese, cobalt, or zinc. During growth in liquid medium, cells secreted phospholipase C during late logarithmic and early stationary phases. Secretion was repressed by the addition of inorganic phosphate but not by organic phosphates, glucose, or sodium succinate. Studies with tetracycline indicated that de novo protein synthesis was necessary for the secretion of phospholipase C and that the exoenzyme was not released from a preformed periplasmic pool. Similarly, extraction of actively secreting cells with 0.2 M MgCl2 at pH 8.4 solubilized large quantities of the periplasmic enzyme alkaline phosphatase but insignificant amounts of phospholipase C. Bacteria continued to secrete enzyme for nearly 45 min after the addition of inorganic phosphate or rifampin.
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PMID:Secretion of phospholipase C by Pseudomonas aeruginosa. 11 87

1. Haemoglobin-free erythrocyte ghosts were prepared in 40 imosM bicarbonate buffer, pH 7.4, containing 1 mM EDTA (40 imosM/l mM EDTA). The ghost preparation was highly permeable on preparation but partially resealed on incubation in media containing Ca-2+. 2. A partially purified preparation of phospholipase C from Clostridum welchii caused an increase in observed Mg-2+-ATPase activity, reflecting a change in the permeability of the ghost to substrate. The phospholipase did not decrease Mg-2+-ATPase even at the highest levels tested. Mg-2+-ATPase activity could therefore be used as a permeability indicatior in these experiments. 3. Both (Ca-2+, Mg-2+)-ATPase activities of the ghosts were progressively lost as a result of the phospholipid hydrolysis induced by phospholipase C. 4. When a haemolysin in the commercial preparation was destroyed by heat-treatment, deactivation of the (Ca-2+, Mg-2+)-ATPase and (Na+, K+, Mg-2+)-ATPases were still observed but permeability changes were greatly reduced. 5. The products of phospholipase action were not inhibitory to the Ca-2+, Mg-2+)-ATPase. 6. Lysolecithin brought about a reactivation of the (Ca-2+, Mg-2+)-ATPase which was superimposed upon permeability changes in the preparation. 7. Reactivation of the (Ca-2+, Mg-2+)-ATPase was brought about by a nonlytic, mixed lipid preparation without significant effect upon permeability. 8. Human erythrocyte (Ca-2+, Mg-2+)-ATPase therefore appears to be an enzyme which responds to perturbation of the lipid environment in the membrane and is a "lipid-dependant" enzyme.
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PMID:Hydrolysis of erythrocyte membrane phospholipids by a preparation of phospholipase C from Clostridium Welchii. Deactivation of (Ca-2+, Mg-2+)-ATPase and its reactivation by added lipids. 12 73


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