Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.26.9 (ribonuclease)
 6,589 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. Bison ribonuclease was isolated from pancreas glands of Bison bison by acid extraction, (NH(4))(2)SO(4) fractionation, affinity chromatography on Sepharose-5'-(4-aminophenylphosphoryl)uridine 2',3'-phosphate and ion-exchange chromatography on Bio-Rex-70. 2. The selectivity of the affinity column towards bison ribonuclease in heterogeneous protein solutions was greatly improved by employing piperazine buffers at pH5.3, which decreased non-specific interactions of other proteins. Rapid desorption from the affinity column was obtained with sodium phosphate buffer (pH3). 3. Bison ribonuclease has a total amino acid content very similar to ox ribonuclease. Inactivation of bison ribonuclease with iodoacetic acid leads to the formation of 0.62 residues of pi-carboxymethylhistidine and 0.36 residues of tau-carboxymethylhistidine. The amino acid composition of peptides isolated from diagonal peptide ;maps' and also of peptides isolated after pH1.6 and 2.4 two-dimensional high-voltage electrophoresis of a digest of bison ribonuclease labelled with pyridoxal 5-phosphate indicates that there is complete homology between ox and bison ribonucleases. 4. The Schiff-base attachment site of pyridoxal 5-phosphate was identified as lysine-41 by NaBH(4) reduction followed by peptide isolation.
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PMID:The isolation and partial characterization of ribonuclease A from Bison bison. 477 70

By sedimentation in 2.5 x 10(-4)m sodium ethylenediaminetetraacetate at 25 C, replicative intermediate could be separated from single-stranded ribonucleic acid, both viral and ribosomal. All of the label in the replicative intermediate after a brief pulse of titrated uridine was resistant to ribonuclease.
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PMID:Separation of replicative intermediate from single-stranded ribonucleic acid by sedimentation at low ionic strength. 497 67

Highly purified trachoma elementary bodies (T'ang strain), incubated in the presence of the four nucleoside triphosphates [Mg(2+), Mn(2+), 2-mercaptoethanol, tris(hydroxymethyl)aminomethane buffer (pH 7.5)] were found to incorporate (3)H-uridine triphosphate (UTP) into ribonucleic acid (RNA) molecules. Eighty-seven per cent of the labeled molecules were sensitive to ribonuclease treatment. In vitro RNA synthesis was almost completely inhibited by actinomycin D. Rifampin was also inhibitory, but allowed some initial RNA synthesis before complete inhibition occurred. When the reaction mixture lacked Mn(2+), trachoma elementary bodies synthesized, for a limited period, high-molecular-weight RNA species (23 to 24S, 16 to 17S, and 10 to 11S). Addition of 0.2 m NaCl to the same reaction mixture stimulated and prolonged (3)H-UTP incorporation into the same radioactive RNA species. Addition of 0.001 m Mn(2+) instead of NaCl also stimulated (3)H-UTP incorporation but prevented the synthesis of the high-molecular-weight RNA species.
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PMID:Deoxyribonucleic acid-dependent ribonucleic acid polymerase activity in purified trachoma elementary bodies: effect of sodium chloride on ribonucleic acid transcription. 509 83

The properties of the ribonucleic acid (RNA) synthesized by the influenza (WSN) virion polymerase have been investigated. Most of the product RNA is synthesized in association with virion RNA species from which it can be released by heat treatment as single-stranded, ribonuclease-sensitive polynucleotides (average molecular weight, 2-hr sample, about 10(5) daltons). At least 95% of the product is complementary to the viral RNA species. On the basis of the molar ratio of the RNA species isolated from a (3)H-uridine-labeled virus preparation, it was calculated that the WSN genome consists of seven pieces of RNA with a sum molecular weight of about 5 x 10(6) daltons.
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PMID:Transcription of the influenza ribonucleic acid genome by a virion polymerase. II. Nature of the in vitro polymerase product. 510 47

When S(35)-labeled soluble RNA from Escherichia coli K 38 is subjected to gel filtration, four fractions of RNA are obtained by elution. Only one RNA fraction, the transfer RNA, contains sulfur, presumably as thionucleotides. Treatment with ribonuclease suggests that the incorporated sulfur is an integral part of the polynucleotide chain; digestion with alkali yields a mixture of products containing sulfur, the major one being eluted in a position similar to uridine diphosphate upon Dowex-l chromatography. Analysis by countercurrent distribution of S(35)-labeledtransfer RNA from E. coli B reveals that the incorporated sulfur is found in many RNA's that accept amino acids, but the possibility remains that not all acceptor RNA's contain sulfur.
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PMID:Sulfur: incorporation into the transfer fraction of soluble ribonucleic acid. 532 39

1. Highly purified mitochondria containing 3.0mug of RNA/mg of mitochondrial protein were prepared from rat liver by differential centrifugation. 2. RNA, labelled with [(32)P]P(i) or [(3)H]orotate, was isolated from these mitochondria by a phenol extraction method. The RNA sedimented at 15S and 13S on sucrose density gradients. Its nucleotide composition was 23% uridylate, 30% adenylate, 22% guanylate and 25% cytidylate. 3. RNA from mouse L cells was labelled with [(3)H]-uridine in the presence of 0.1mug of actinomycin D/ml to suppress the synthesis of cytoplasmic rRNA. The RNA isolated from crude L-cell mitochondria by a cold-phenol-sodium dodecyl sulphate method had components sedimenting at 15S and 12.5S. These components had an electrophoretic mobility on agarose-acrylamide gels of 21 and 12S(E) compared with 28 and 18S(E) for cytoplasmic rRNA. The nucleotide composition was 26% uridylate, 34% adenylate, 18% guanylate and 22% cytidylate. 4. RNA extracted from crude L-cell mitochondria by a hotphenol-sodium dodecyl sulphate method had an additional component sedimenting at 21S and having an electrophoretic mobility of 18S(E). It was probably DNA because of its sensitivity to deoxyribonuclease and its insensitivity to ribonuclease and alkali. It was present in nuclear fragments contaminating the crude mitochondrial fraction and could be removed by deoxyribonuclease or isopycnic-gradient centrifugation.
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PMID:Ribosomal-type ribonucleic acid from rodent mitochondria. 549 58

Two populations of polyribosomes have been isolated from third instar larvae of D. melanogaster. One population appeared to be soluble while the second seemed membrane-bound. Short-term labeling of the two RNP fractions with radioactive nucleic acid and protein precursors was achieved by using a feeding stimulant. RNA was extracted from both polyribosomal fractions following 25, 40, and 60 min of in vivo uridine-(3)H incorporation. Soluble polyribosomes exhibited more rapid uptake of uridine into ribosomal and heterogeneous RNA fractions than did membrane-bound polyribosomes at comparable time periods. In vivo amino acid incorporation into the two polyribosomal populations was examined after 10, 20, 40, 60, and 80 min of incubation in leucine-(3)H. In this case, the membrane-bound polyribosomes reached a higher specific activity than did the soluble ones. These functional differences confirmed the observation, based on cellular fractionation studies, that the two classes of polyribosomes represented functionally distinct populations. These data have been compared with those from studies on other metazoan systems. In addition, dithiothreitol has been demonstrated to be a powerful ribonuclease inhibitor.
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PMID:Drosophila polyribosomes. The characterization of two populations by cell fractionation and isotopic labeling with nucleic acid and protein precursors. 552 37

Purified replicative form (RF) and replicative intermediate (RI) prepared from Escherichia coli infected with R17 were denatured in 0.15 m NaCl, 0.015 m sodium citrate containing 65% dimethylsulfoxide. Denaturation of RF or RI was demonstrated spectrophotometrically, chromatographically, and by sedimentation analysis. Denatured RF or RI was annealed by carefully decreasing the temperature from 62 to 20 C. Annealing was accompanied by a decreased absorbance at 260 mmu. The decrease in absorbance during annealing appeared to be dependent upon the rate of cooling and the concentration of ribonucleic acid (RNA). Denatured RF or RI was annealed with R17 RNA which was labeled with (3)H-uridine. The annealed product was 73 to 82% resistant to 0.1 mug/ml of ribonuclease. Annealing R17 RNA with either denatured RF or RI resulted in the formation of a ribonuclease-resistant product with a sedimentation profile resembling that of native RI. Melting the annealed products in 85.7% dimethyl sulfoxide produced 27S single-stranded R17 RNA and a heterogeneous population of more slowly sedimenting RNA.
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PMID:Denaturation and renaturation of viral ribonucleic acid. I. Annealing R17 ribonucleic acid with denatured replicative form or with denatured replicative intermediate. 562 75

The large-particle fraction from the cytoplasm of chick embryo fibroblasts infected with Semliki Forest virus was found to catalyze the incorporation of the 5'-triphosphates of guanosine, adenine, cytidine, and uridine into an acid-insoluble alkali-labile product. The conditions affecting the preparation and assay of this enzyme were investigated. The ribonucleic acid (RNA) polymerase was not present in uninfected cells, and it appeared in infected cells at the time of rapid viral RNA synthesis. The polymerase was found to catalyze the synthesis of a species of RNA which was resistant to ribonuclease and which exhibited the sedimentation properties, buoyant density, and thermal transition temperature of the double-stranded RNA found in vivo in chick cells infected with Semliki forest virus. Attempts to demonstrate that the reaction product of this enzyme also included single-stranded viral RNA were not successful. Although other interpretations are possible, these results give some support to the suggestion that more than one enzyme may be involved in the replication of viral RNA.
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PMID:Ribonucleic acid polymerase catalyzing synthesis of double-stranded arbovirus ribonucleic acid. 562 60

When actinomycin D-treated chick fibroblasts were labeled with (3)H-uridine for varying periods during the log phase of Semliki Forest virus infection, radioactivity was found associated with different cytoplasmic fractions. After a 1-min period of labeling, it appeared in a large cytoplasmic structure which was seen in electron micrographs of infected cells. Sediments of sucrose density gradients of cytoplasmic extracts of these cells also contained these structures. Three forms of viral ribonucleic acid (RNA) were associated with this cytoplasmic structure: a ribonuclease-sensitive 42S form identical to the RNA of the mature virus, a ribonuclease-sensitive 26S form, and a ribonuclease-resistant 20S form. After a 5- to 10-min labeling period, radioactivity was associated with a ribonuclease-sensitive 65S cytoplasmic fraction which contained only the 26S RNA form. Finally, after a 1-hr labeling period, a 140S ribonuclease-resistant particle was the most prominent radioactive structure in the cytoplasm. This particle contained only 42S viral RNA. Negative-contrast electron micrographs of the 140S particle and the virion demonstrated structural differences between them. The base compositions of the 42S and 26S viral RNA forms were not significantly different. The base composition of the 20S form differed significantly from that of the other two viral RNA forms, but the values obtained for the mole fractions of the bases present in the 20S form differed, and depended on the period during the virus growth cycle in which (32)P was present. These results suggested that viral RNA originated in the large cytoplasmic body. The 20S RNA appeared to be a structure engaged in viral RNA replication and the 140S particle appeared to be a virus precursor.
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PMID:Cytoplasmic fractions associated with Semliki Forest virus ribonucleic acid replication. 563 Mar 81


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