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:3.1.27.5 (RNase)
17,967 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The structure of partial deproteinized rat hepatocyte chromatin has been studied. Depending on the magnesium concentration the chromatin of isolated nuclei is present in the two conditions: diffuse (at 0-1.5 mM MgCl2) and condensed (at 2-5 mM MgCl2). The main components of nuclei with condensed chromatin are chromomers--globular structures about 100 nm in diameter. By treating such nuclei with heparin and dextransulfate one can observe a rosette-like structure with lateral loops having the following parameters: the length of the loops, 15-20 micron; the number of loops, 15-30. The rosette-like structures are sensitive to endogenous nuclease and DNase 1, but not to RNase. Pronase or higher concentration of polyanions give rise to unfolding of the rosette-like structures. The rosette structures cannot be isolated from the nuclei with diffuse chromatin. On the basis of these observations a hypothesis of chromatin structural organization in the interphase nucleus is proposed, and the connection of the rosette-like structures with some structural levels of chromatin organization is discussed.
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PMID:[Isolation of rosette-like structures from partially deproteinized chromatin in rat hepatocytes]. 406 Feb 28

A lipopolysaccharide (LPS) fraction was extracted from Nichols, nonpathogenic Treponema pallidum by the hot, phenol-water procedure. The LPS was freed of nucleic acids and water-soluble proteins by successive exposures to ribonuclease, deoxyribonuclease, and Pronase. Purified LPS responded positively in a colorimetric assay for lipopolysaccharide. Electron microscope examination of the LPS both before and after purification demonstrated a heterogeneous mixture of forms including spheres, doughnuts, and ribbons. The trilaminar nature of the ribbon forms was observed by both negative staining and thin sectioning. Lyophilization of the LPS caused an increase in the number and length of ribbon forms seen. Results suggest that the surface layers of treponemes are similar to those of gram-negative bacteria.
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PMID:Ultrastructure of lipopolysaccharide isolated from Treponema pallidum. 412 67

The means by which coxsackievirus type A9 (CA9) is inactivated by proteolytic enzymes was investigated. After reaction of (14)C-leucine-labeled CA9 with Pronase, free leucine was liberated as measured by radiochromatography. Treatment of (14)C-leucine-labeled CA9 with trypsin or proteolytic filtrates of Pseudomonas aeruginosa caused the release of a variety of labeled substances. The extent of viral ribonucleic acid (RNA) release after exposure of CA9 to Pronase was determined by RNA infectivity tests or trichloroacetic acid solubility tests. Infective viral RNA was found not to be consistently released by reaction of CA9 with Pronase, but further treatment with 1% sodium dodecyl sulfate at pH 7.0 promoted viral RNA release. Sodium dodecyl sulfate treatment of CA9 that had not been reacted with Pronase did not inactivate virus or cause viral RNA release. Reaction of Pronase with (32)P-labeled CA9 resulted in the liberation of virus components soluble in cold trichloroacetic acid, whereas untreated CA9 or CA9 reacted with ribonuclease were precipitated by cold trichloroacetic acid. These results demonstrate that the primary means by which protease-sensitive enteroviruses are inactivated is by degradation of the virus capsid, with subsequent release of viral RNA.
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PMID:Degradation of coxsackievirus type A9 by proteolytic enzymes. 420 58

Mouse mammary tumor virus (MTV) was isolated from the milk of RIII mice by density-gradient centrifugation in Ficoll. The homogeneity of the preparation was demonstrated in electron micrographs. The nucleic acid was extracted with phenol in the presence of Pronase. Its viral origin was attested by failure of ribo-nuclease and deoxyribonuclease treatment of the virus preparation to destroy the filamentous molecules; after phenol extraction, the molecules were destroyed by ribonuclease but not by deoxyribonuclease. Rotary shadowed preparations were examined in the electron microscope. The length distribution of the RNA filaments showed peaks at 1.2, 2.4, and 3.6 mum. The molecular weight of the longest molecule of MTV-RNA was estimated as 3.6 x 10(6) daltons.
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PMID:Electron microscopy of the nucleic acid of mouse mammary tumor virus. 431 50

A protein kinase which is intimately associated with equine herpesvirus (equine abortion virus) was found by using adenosine triphosphate-gamma-(32)P as a phosphate donor and virus protein as an acceptor. Consistent demonstration of the activity requires prior removal of phosphohydrolase. The kinase activity requires Mg(2+), is not stimulated by cyclic adenosine monophosphate, but is enhanced by added protamine or arginine-rich histone. The labeled product is resistant to ribonuclease, deoxyribonuclease, and chloroform-methanol but is sensitive to Pronase. Other tests suggest that serine and threonine residues are the acceptor sites. In the in vitro reaction, the incorporation represents an average of approximately 4,500 phosphate residues per virion, and all 17 virus protein bands resolved by polyacrylamide gel electrophoresis appear to be labeled.
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PMID:Protein kinase activity in equine herpesvirus. 433 15

We previously reported that putative nuclear receptors for thyroid hormone can be demonstrated by incubation of hormone either with intact GH(1) cells, a rat pituitary tumor cell line, or with isolated GH(1) cell nuclei and rat liver nuclei in vitro. We characterized further the kinetics of triiodothyronine (T3) and thyroxine (T4) binding and the biochemical properties of the nuclear receptor after extraction to a soluble form with 0.4 M KCl. In vitro binding of [(125)I]T3 and [(125)I]T4 with GH(1) cell and rat liver nuclear extract was examined at 0 degrees C and 37 degrees C. Equilibrium was attained within 5 min at 37 degrees C and 2 h at 0 degrees C. The binding activity from GH(1) cells was stable for at least 1 h at 37 degrees C and 10 days at - 20 degrees C. Chromatography on a weak carboxylic acid column and inactivation by trypsin and Pronase, but not by DNase or RNase, suggested that the putative receptor was a nonhistone protein. The estimated equilibrium dissociation constants (K(d)) for hormone binding to the solubilized nuclear binding activity was 1.80 x 10(-10) M (T3) and 1.20 x 10(-9) M (T4) for GH(1) cells and 1.57 x 10(-10) M (T3) and 2.0 x 10(-9) M (T4) for rat liver. These K(d) values for T3 are virtually identical to those which we previously reported with isolated rat liver nuclei and GH(1) cell nuclei in vitro. The 10-fold greater affinity for T3 compared to T4 in the nuclear extract is also identical to that observed with intact GH(1) cells. In addition, the [(125)I]T3 and [(125)I]T4 high-affinity binding in the nuclear extract were inhibited by either nonradioactive T3 or T4, which suggests that the binding activity in nuclear extract was identical for T3 and T4. In contrast, the binding activity for T4 and T3 in GH(1) cell cytosol was markedly different from that observed with nuclear extract (K(d) values were 2.87 x 10(-10) M for T4 and 1.13 x 10(-9) M for T3). Our results indicate that nuclear receptors for T3 and T4 can be isolated in a soluble and stable form with no apparent change in hormonal affinity. This should allow elucidation of the mechanisms of thyroid hormone action at the molecular level.
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PMID:Thyroid hormone action: in vitro characterization of solubilized nuclear receptors from rat liver and cultured GH1 cells. 437 51

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

A structure consisting of poly(A) complexed with other components is released from polysomes by ribonuclease treatment. The poly(A) complex has a sedimentation value of 12-15, while the corresponding sedimentation value for free poly(A) is 4. The complex does not appear to represent an artifact formed by interaction of free poly(A) with either cytoplasmic or polysomal proteins. The polynucleotide released from the complex by treatment with sodium dodecyl sulfate shows the same electrophoretic mobility as that of poly(A) isolated from deproteinized polysomal RNA. The poly(A) in the complex is partially protected from digestion by T(2) ribonuclease. At least part of the poly(A) is available for base pairing with poly(U). The components associated with the poly(A) cause it to bind to Millipore filters at low ionic strength. These components are removed from the complex by Pronase digestion. The findings indicate that the poly(A) segment in messenger RNA serves as a binding site for a particle. This particle appears to consist of proteins.
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PMID:A particle associated with the polyadenylate segment in mammalian messenger RNA. 450 17

DNA isolated from Mycoplasmatales viruses MVL51 and MVGs51 was infectious when mixed with Acholeplasma laidlawii BN1-Na1(R) cells. Infectivity was destroyed by deoxyribonuclease but not by ribonuclease, Pronase, or specific antiserum to the virus. Host mycoplasma cells were only competent for transfection during late-log growth phase. The rates of the establishment of DNase insensitivity of viral DNA transfectants were similar to those of bacteriophage systems. The dose-response curve for transfection suggested that an average of six molecules of DNA must interact with a cell in order to produce one infectious center. Mycoplasmatales virus DNA exhibited a low efficiency of infection; one infectious center required 4 x 10(5) virus equivalents of DNA.
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PMID:Transfection mediated by Mycoplasmatales viral DNA. 450 32

The high-speed supernatant fraction of rat liver, lung, kidney, testis, and intestinal mucosa contains a component capable of binding [(3)H]retinol in vitro when binding is analyzed by sucrose density gradient centrifugation or gel filtration. This binding component can be distinguished from one identified in rat serum. Whereas the tissue component sediments in the 2S region of sucrose gradients, the serum component sediments in the 4.6S region. Molecular weight estimations by gel filtration indicate molecular weights of 16,000 and 67,000 for the tissue and serum binding components, respectively. Unlabeled retinol, but not retinoic acid, competes for the binding of [(3)H]retinol in tissue cytosols. Competition for the binding of [(3)H]retinol by unlabeled retinal has also been observed in tissue cytosols, but may result from the in vitro reduction of retinal to retinol. Unlabeled retinol, retinal, and retinoic acid fail to compete for the binding of [(3)H]retinol in serum under the conditions used. The tissue binding component (testis) is sensitive to digestion with Pronase, but not with RNase or DNase, indicating a protein nature for this component.
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PMID:In vitro binding of retinol to rat-tissue components. 451 41


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