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)

The method of DNA binding to nitrocellulose filters was applied to DNA isolated from mouse liver and Ehrlich ascite carcinoma (EAC), calf thymus, and lymphocytes from patients with chronic lymphoid leukemia. In those and phage PM2 DNA the increase in the DNA binding to the filters with a rise in NaCl concentration from 0.5 up to 4.5 M was sigmoidal being suggestive of a conformational transition. No such activity was found in the case of phage lambda or single-stranded DNA. The binding decreased dramatically after mild cleavage of DNA with DNAase I or treatment with phospholipase C or Eco RI and Hin PI restrictases. Incubation of DNA with ethidium bromide led to decrease in the amount of bound DNA. This effect was enhanced with a rise in the dye concentration. The isotherms of ethidium bromide binding to eukaryotic DNA obtained in Scatchard plots by optic titration had a component with a positive slope at low values of r. Bivalent ions (Mg2+, Zn2+) shifting the equilibrium towards the Z-form increased the proportion of macromolecules retained on the filters at NaCl concentrations of 1-3 M. Local changes in the helix conformation were studied with the help of chemical probes: diethylpyrocarbonate (guanine Z-DNA) and osmium-pyridine reagent (pyrimidines of boundary B-Z sites). These probes incorporation into samples of liver DNA, EAC, and lymphocytes resulted in chemical modification of all these samples. Modification of DNA by osmium-pyridine reagent led to inhibition of subsequent restriction by Eco RI restrictase. The data obtained are suggestive of the presence of Z-regions in the B-helix of eukaryotic DNA. A topological model of Z-site stabilization in small superhelical loops of DNA fixed by protein or lipoprotein molecules is proposed.
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PMID:[Detection of left-helical segments in eukaryotic DNA]. 148 26

Twenty-two nitrogen-fixing Bacillus azotofixans strains were shown to produce an inhibition zone against themselves in plate assays. The B. azotofixans type strain P3L-5, chosen for further studies, produced inhibition zones against various Bacillus strains and other bacterial genera. This antibacterial substance was also produced in liquid medium and its production was enhanced in semisolid medium (0.4% agar) after 3 to 5 days of incubation. The substance was suggested to be an antibiotic and its preliminary characterization showed resistance to heat (100 degrees C, 15 minutes), to trypsin, pronase, deoxyribonuclease I, ribonuclease A, phospholipase C, ethanol, acetone, and ether, and sensitivity to strong alkali treatment. Its molecular weight was estimated to be between 3500 to 6000. After induction of B. azotofixans P3L-5 with mitomycin C or ultraviolet light, two types of particles were detected in the lysate: one similar to a phage tail and the other, less frequent, similar to a complete bacteriophage. Lysates containing these particles showed a killing effect in some but not all B. azotofixans strains, but neither the other Bacillus species nor Micrococcus were inhibited by these lysates.
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PMID:Production of a bacteriophage, a phage tail-like bacteriocin and an antibiotic by Bacillus azotofixans. 212

Of 120 laboratory-maintained strains of Listeria monocytogenes and two of L. ivanovii examined for haemolytic and lipolytic activity, 62 exhibited haemolytic activity alone, 20 of these showed haemolytic and lipolytic activity and 40 had neither activity. The L. ivanovii strains showed both activities. The results indicated a relationship between haemolysin production and lipolytic activity which was not explained by the serotype of the organism. In addition, the following hydrolytic activities were detected in the cell-free growth media of strains L. monocytogenes Boldy and L. ivanovii (formerly L. monocytogenes) Type 5 (substrates acted upon are given in parentheses): acid phosphate (4-nitrophenylphosphate, naphthyl phosphate, glycerophosphate, phosphorylcholine and GTP); neutral phosphatase (4-nitrophenylphosphate, naphthyl phosphate, phosphorylcholine, NADP and UDPG); phosphodiesterase (bis-4-nitrophenylphosphate, ATP and NADP); NADase (NAD); phospholipase C (4-nitrophenylphosphoryl-choline, phosphatidyl choline and ethanolamine, and sphingomyelin); and lipase and esterase (triacetin, tributyrin, triolein, naphthyl-laurate,-myristate,-caprylate,-palmitate and -oleate, 4-nitrophenyl-acetate-laurate and Tween 80). The preparations also showed weak catalase activity. No evidence was found for the presence of RNAase, DNAase, peptidase/amidase, phosphoamidase, alpha-amylase, glucosidase, galactosidase, pyranosidase or glucose aminidase.
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PMID:Haemolysins and extracellular enzymes of Listeria monocytogenes and L. ivanovii. 250 86

Antibodies prepared against the phospholipase A2 stimulatory peptide melittin were used to identify and isolate a novel mammalian protein with similar functional and antigenic properties. The mammalian protein of Mr 28,000 was isolated from cell sonicates by high performance immunoaffinity chromatography and size exclusion chromatography. This stimulatory protein was stable for several months when frozen at -70 degrees C. The purified protein selectively stimulated phospholipase A2 when phosphatidylcholine was used as a substrate but had no effect on phospholipase A2 activity when phosphatidylethanolamine was used as a substrate. Furthermore, this protein had no effect on phospholipase C activity or on pancreatic or snake venom phospholipase A2. The stimulatory activity was unaffected by RNase or DNase treatment. However, boiling or trypsin digestion inactivated the phospholipase stimulatory activity. The mechanism of phospholipase A2 stimulation appeared to result from an increase in the apparent Vmax of the enzyme.
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PMID:Identification and isolation of a mammalian protein which is antigenically and functionally related to the phospholipase A2 stimulatory peptide melittin. 354 34

We report the existence of an extracellular staphylococcal product, designated staphylococcal decomplementation antigen (DA), that causes rapid consumption of early-reacting complement components up to and including C5 in human serum. Complement activation occurs as a consequence of immune complex formation between DA and specific human immunoglobulin G antibodies and proceeds primarily via the classical pathway. The terminal components C7, C8, and C9 are not consumed during the process. Levels of DA production do not correlate with the expression of classical pathogenic factors, such as coagulase, clumping factor, protein A, or alpha-toxin. DA is a nondialyzable macromolecule eluting in a molecular-weight region of 70,000 to 120,000 on Sephacryl S-300 and displaying an apparent sedimentation coefficient of 3 to 4 S on sucrose density gradients. The molecule is remarkably stable and resists destruction upon boiling for 30 min or by treatment with pronase, lysostaphin, DNase, or RNase. We anticipate that DA protects staphylococci from complement attack through induction of abortive, complement-consuming reactions in the fluid phase.
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PMID:Decomplementation antigen, a possible determinant of staphylococcal pathogenicity. 396 9

Fixation of embryonic chick cells (heart, neural retina, and limb bud) in the presence of lanthanum ions shows the presence of an electron-opaque layer, about 50 A thick, external to the cell membrane. This layer, designated LSM (for lanthanum-staining material), is not removable by trypsin, pronase, EDTA, DNase, alpha-amylase, neuraminidase, or N-acetyl-L-cysteine. However, phospholipase C, in concentrations as low as 0.001 mg/ml, succeeds in stripping the LSM from the cell surface. Heating the enzyme preparation does not inhibit this activity, but removal of divalent cations does; both of these results are consistent with the known properties of phospholipase C. The LSM is present at the cell surface in the control tissues and on cells dissociated from the tissues by proteolytic enzymes and EDTA. These results are interpreted to mean that the LSM is probably an integral part of the cell and not an extraneous coat. How this phenomenon bears on the problem of cellular adhesion is discussed, as is the possible chemical composition of the LSM.
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PMID:The removal by phospholipase C of a layer of lanthanum-staining material external to the cell membrane in embryonic chick cells. 416 2

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

A Mycoplasma gallisepticum subcellular fraction (P2), which contains the deoxyribonucleic acid replication complex, can be isolated by differential centrifugation of freeze-thaw-lysed cells. The nascent deoxyribonucleic acid is released from P2 by Lubrol-WX, sodium dodecyl sulfate, Pronase, and deoxyribonuclease, but not by saponin, ribonuclease, phospholipase C, or high-frequency sonic treatment. Sonic treatment further fractionates the cell ghost and allows partial purification, on sucrose density gradients, of a deoxyribonucleic acid replication complex attached to the cells' polar membrane-bleb-infrableb structures.
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PMID:Partial purification of a membrane-associated deoxyribonucleic acid complex from Mycoplasma gallisepticum. 442 Sep 60

Group H streptococci (strain Challis) which are competent for transformation release a bacteriocin into liquid medium which is bacteriocidal for another group H streptococcus (strain Wicky). The streptocin (STH(1)) is resistant to treatment with deoxyribonuclease and ribonuclease but is sensitive to trypsin, phospholipase C, and alkaline phosphatase. Such enzyme sensitivity experiments indicate that the bacteriocin may be a complex molecule (protein and lipid) containing phosphate groups essential for activity. STH(1), which is readily distinguishable from competence factor and bacteriophage activity, appears to have no role in the initiation of the competent state in strain Wicky. The presence of this factor in Challis culture supernatant fluids indicates that a reevaluation of earlier studies performed with the Challis-Wicky transformation system may be necessary.
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PMID:Bacteriocin production by transformable group H streptococci. 508 61

Human seminal fluid, at low dilutions, prevented the binding of aggregated human IgG (AHG) to bull spermatozoa. Seminal fluids from vasectomized men were also inhibitory. Preincubation of the seminal fluid with the spermatozoa prior to washing and addition to AHG had no inhibitory effect, indicating that the fluid component was reacting directly with AHG. Human seminal fluid was fractionated by gel exclusion chromatography on Ultrogel AcA-34, and AHG inhibitory activity was found in fractions corresponding to a molecular weight of 94,000. The activity in this fraction was stable to boiling for 10 min. It was sensitive to pronase but resistant to glycosidase, phospholipase C, neuraminidase, ribonuclease, and deoxyribonuclease, indicating that it was a protein. The gel filtration fraction readily bound recrystallized Fc and AHG; IgG was bound to a lesser extent, and no reactivity was observed with F(ab')2, IgA, or IgM. Thus, the seminal fluid fraction appeared to specifically react with the Fc portion of IgG. The seminal fluid Fc-binding protein was isolated by affinity chromatography on Fc coupled to CNBr-activated Sepharose 4B. Scatchard analysis revealed that the binding of the seminal fluid Fc-binding protein to recrystallized Fc is reversible and had a Kd of approximately 3 x 10(-6) M.
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PMID:An IgG-Fc binding protein in seminal fluid. 622 60


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