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

---

Query: EC:3.1.27.1 (RNase)
16,360 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Repair synthesis in human cells in tissue culture can be readily separated from semi-conservative DNA synthesis with the aid of a benzoylated naphthoylated DEAE cellulose (BND-cellulose) column. Cells are incubated with a radioactive DNA precursor during treatment with a repair-inducing agent. An inhibitor of semi-conservative DNA synthesis (hydroxyurea) is added to slow the progression of the DNA growing point. The cells are lysed and after treatment with ribonuclease and pronase the lysates are sheared and passed through a BND-cellulose column. Native DNA is eluted with I M NaCl. Any increase in radioactivity in the native DNA is due to repair synthesis and the specific repair activity (nucleotides inserted per mug of DNA) can be determined from radioactivity and absorbancy measurements. Repair can also be measured in the region of the DNA growing point by fractionation of the material eluted from BND-cellulose with 50% formamide. Repair was not detected in N-acetoxy-2-acetylaminofluorene (AAAF)-treated lymphoblasts derived from an individual with xeroderma pigmentosum although methyl methanesulfonate (MMS)-induced repair was observed in these cells.
...
PMID:The measurement of chemically-induced DNA repair synthesis in human cells by BND-cellulose chromatography. 117 59

Both alpha zein purified from a commericial preparation and beta zein prepared fresh from corn are soluble in the nonaqueous solvents formamide and dimethylformamide; in this regard zein resembles water soluble proteins such as insulin, ribonuclease, and lysozyme. On the basis of osmotic pressure measurements made in both formamide and dimethylformamide, alpha zein has a number average moleular weight of 21000-24000 daltons and shows no tendency to aggregate or dissociate. Beta zein exists in an aggregated state (dimer and higher forms) in dimethylformamide. Formamide dissociates the beta zein dimer into monomer units but aggregation to higher species occurs with increasing protein concentration.
...
PMID:Molecular weight of an extremely hydrophobic protein, zein, in dimethylformamide and in formamide. 126 May 2

A procedure is described for the immobilization of monomeric actin so that about 30% of the immobilized protein is competent to bind the monomeric-actin-binding proteins bovine pancreatic deoxyribonuclease I and chicken villin. The intact tertiary structure of the immobilized actin is required to bind these proteins. Using this resin, a method has been developed for the affinity purification of pancreatic deoxyribonuclease I on a reusable actin column. It involves the binding of deoxyribonuclease I to immobilized actin, extensive washing of the column, followed by elution of the bound deoxyribonuclease I with 10 M formamide. After removal of the formamide, the deoxyribonuclease I has a higher specific activity than the starting material and contained no detectable protease or ribonuclease contamination. This preparation should find considerable application in molecular genetic studies where the enzyme is needed free of these particular contaminants. The affinity column should also be useful for the isolation of other, physiologically relevant, monomeric-actin-binding proteins.
...
PMID:Preparation of immobilized monomeric actin and its use in the isolation of protease-free and ribonuclease-free pancreatic deoxyribonuclease I. 264 36

Hen oviduct N alpha-acetyltransferase was clarified to have a nucleic acid as an existing constituent by the following three results: (i) an ultraviolet absorption spectrum of the purified N alpha-acetyltransferase free of S-acetyl coenzyme A (Ac-CoA) had an absorption maximum at 260 nm. (ii) A nucleic acid band stained with ethidium bromide was detected on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. (iii) An ethidium bromide band co-migrated with a fluorescent band of the protein treated with N-(7-dimethylamino-4-methylcoumarinyl)maleimide, a reagent specific for thiol groups, on polyacrylamide gel electrophoresis in the absence of sodium dodecyl sulfate. N alpha-Acetyltransferase lost its activity partially or completely by digestion with bovine pancreatic RNase A, Staphylococcus aureus nuclease, or proteinase K, showing that both the nucleic acid and the protein subunit were necessary for the enzyme activity. The nucleic acid component was identified as an RNA but not a DNA because the RNase T2 digest of the nucleic acid was composed of four 3'-ribomononucleotides and completely separated from 3'- and 5'-deoxyribomononucleotides on TLC. The chain length of the nucleic acid of 260 nucleotides estimated by formamide-polyacrylamide gel electrophoresis was calculated to be about 83,000 of the molecular weight. The contents of RNA (35.0%) and protein (65.0%) in N alpha-acetyltransferase determined on weight basis corresponded reasonably well to the contents of RNA (34.4%) and protein (65.6%) calculated based on the assumption that N alpha-acetyltransferase consisted of one molecule of 7 S RNA (Mr 83,000) and two identical Mr 79,000 protein subunits. The total molecular weight (241,000) of the holoenzyme calculated based on the above result was identical to the molecular weight (240,000) of N alpha-acetyltransferase estimated by Sepharose 6B gel filtration.
...
PMID:Hen oviduct N alpha-acetyltransferase is a ribonucleoprotein having 7 S RNA. 275 10

Rapidly labeled RNA was extracted from monkey cells after infection with Simian Virus 40 (SV40) and exposure to short pulses of [5-(3)H]uridine late in infection. When this RNA was self-annealed, it became resistant to digestion with ribonuclease. The fraction of RNA that resisted the ribonuclease treatment decreased with increased labeling time, or when a short pulse of radioactivity was followed by incubation with unlabeled uridine and actinomycin D. The RNase-resistant RNA was isolated by chromatography on Sephadex G-100 and shown to be double-stranded by its susceptibility to ribonuclease as a function of salt concentration and temperature. This behavior was not due to RNA-DNA hybrid formation, since deoxyribonuclease had no effect upon the double-stranded molecules, even after their denaturation. The relation of the double-stranded RNA to SV40 was demonstrated by the hybridization of about 50% (corrected value, >90%) of the separated RNA strands with component I of SV40 DNA from plaque-purified virus. After self-annealing in formamide at low temperature, about 10% of the rapidly labeled, viral RNA sedimented at 13 S. This value corresponds in size to about 60% of the SV40 DNA.These observations indicate that late in infection of monkey cells, SV40 DNA is transcribed symmetrically over a considerable portion of its length, and that subsequently some sequences from one or both of the RNA strands are degraded.
...
PMID:Extensive symmetrical transcription of Simian Virus 40 DNA in virus-yielding cells. 434 93

The poly(A) sequence of 30 to 40S Rous sarcoma virus RNA, prepared by digestion of the RNA with RNase T(1), showed a rather homogenous electrophoretic distribution in formamide-polyacrylamide gels. Its size was estimated to be about 200 AMP residues. The poly(A) appears to be located at or near the 3' end of the 30 to 40S RNA because: (i) it contained one adenosine per 180 AMP residues, and because (ii) incubation of 30 to 40S RNA with bacterial RNase H in the presence of poly(dT) removed its poly(A) without significantly affecting its hydrodynamic or electrophoretic properties in denaturing solvents. The viral 60 to 70S RNA complex was found to consist of 30 to 40S subunits both with (65%) and without (approximately 30%) poly(A). The heteropolymeric sequences of these two species of 30 to 40S subunits have the same RNase T(1)-resistant oligonucleotide composition. Some, perhaps all, RNase T(1)-resistant oligonucleotides of 30 to 40S Rous sarcoma virus RNA appear to have a unique location relative to the poly(A) sequence, because the complexity of poly(A)-tagged fragments of 30 to 40S RNA decreased with decreasing size of the fragment. Two RNase T(1)-resistant oligonucleotides which distinguish sarcoma virus Prague B RNA from that of a transformation-defective deletion mutant of the same virus appear to be associated with an 11S poly(A)-tagged fragment of Prague B RNA. Thus RNA sequences concerned with cell transformation seem to be located within 5 to 10% of the 3' terminus of Prague B RNA.
...
PMID:Properties and location of poly(A) in Rous sarcoma virus RNA. 437 9

Nucleic acid that is extracted from E. coli labeled by a brief pulse of [(3)H]dT and depatured by treatment with heat, formamide, or formaldehyde bands in a region with a density higher than that of single-stranded E. coli DNA in a Cs(2)SO(4) equilibrium density gradient. If treated with alkali or RNase, it then exhibits the density of single-stranded DNA. These results suggest the presence of a short strand of RNA covalently linked to the nascent DNA. Evidence for the presence of covalently linked RNA-DNA molecules is also obtained by pulse labeling with [(3)H]U. Analyses of nascent nucleic acids from cells pulse labeled for various times, and of the molecules with different sizes, support the hypothesis that the short DNA fragments are formed by extension of even shorter RNA chains, which are synthesized on the parental DNA strands and are removed before ligation of the DNA fragments. The synthesis of the RNA segment of the RNA-DNA molecule is much less sensitive to rifampicin than is the synthesis of bulk RNA.
...
PMID:RNA-linked nascent DNA fragments in Escherichia coli. 455 61

When RNA is annealed in solution with a sufficiently large excess of DNA, the kinetics of DNA-RNA hybridization are relatively simple. Methods are described for following the course of both DNA renaturation and DNA-RNA hybridization in this system. To explore the characteristics of the reaction a series of model systems was used. Each one utilized DNA (sheared to constant size) from a bacterium or bacteriophage and homologous cRNA, i.e. RNA synthesized in vitro on a template of the same DNA. Temperature optima were determined for the hybridization of Escherichia coli nucleic acids in 2xSSC and 3xSSC-50% formamide buffers, and of Proteus mirabilis nucleic acids in 2xSSC buffer. Rate-constants for DNA-RNA hybridization were measured by two methods. These gave somewhat different results, but in all cases the rate-constant of DNA-RNA hybridization was clearly less than that of DNA renaturation. Thus hybridization is a slower reaction than DNA renaturation. Nevertheless, in some cases, with a high concentration of DNA and a long annealing time, 90-95% of the added RNA became resistant to ribonuclease. Experiments are described which show that it is possible to deduce the analytical complexity of DNA with reasonable accuracy from its hybridization with complementary RNA. Similarly, it is possible to estimate the reiteration frequency of multiple DNA sequences (such as ribosomal DNA) from the hybridization of the total DNA with RNA complementary to the multiple sequences. The effect on the system of various DNA/RNA ratios from 100 to 1 is described.
...
PMID:Molecular hybridization of ribonucleic acid with a large excess of deoxyribonucleic acid. 456 16

The biological activity of Odontomyces viscosus, which has been reported to cause periodontal disease in hamsters, was examined. The microorganism was cultured anaerobically in Brain Heart Infusion broth, and the cells were harvested. The washed cells were injected intradermally into the abdomen of rabbits. After 72 hr, a well-defined, firm, raised nodule (about 1.0 by 1.5 cm) with an erythematous border was seen at the injection site. Suspensions of cell wall and cytoplasmic material were injected intradermally, and the lesions appeared only at the site of cell wall injection. The cell walls, which were then treated with trypsin, pepsin, and ribonuclease, again produced the characteristic lesion. These nodular dermal lesions persisted for a minimal time of 10 days. The enzymatically treated cell walls were then hydrolyzed with 1 n HCl, and such hydrolysis up to 1 hr failed to alter the toxic activity of the cell walls. Similar dermal nodular lesions were obtained by injection of enzymatically treated cell walls of strains of Staphylococcus aureus, Streptococcus groups B, C, E, F, K, Lactobacillus casei, and Actinomyces israelii. Treatment with hot and cold trichloroacetic acid solutions and proteolytic enzymes, or with formamide, yielded insoluble fractions which produced the characteristic nodular lesions. The size of the lesion resulting from injection of these fractions was proportional to the amount of the injected material. The active fraction, which does not appear susceptible to hydrolysis by lysozyme, is thought to be cell wall mucopeptide. Histological studies showed skin abscesses due to the toxic reaction; however, in addition to the acute inflammatory reaction, there was local eosinophilia.
...
PMID:Toxic properties of the cell wall of gram-positive bacteria. 533

A ribonucleoprotein (RNP) particle sedimenting at 10 S in sucrose gradients had been isolated from the post-polysomal fraction of homogenates of 14-day-old chick embryonic leg and breast muscle by sucrose gradient fractionation and gel filtration. The 10 S RNP contains a 4 S RNA species (base composition: AMP, .3%; GMP, 22.2%; CMP, 24.2%; and UMP, 23.2%), and shows three major bands in the 70-90-nucleotide size range by polyacrylamide gel electrophoresis in 99% formamide. The 4 S RNA does not contain oligo(U)- and oligo(A)-rich tracts. The RNP has a characteristic buoyant density of 1.410 g/ml, which corresponds to an RNA/protein ratio of about 1:4. The UV absorption spectra of the RNP is very distinct from that of its RNA component. Both 4 S RNA and the 10 S RNP are potent inhibitors of translation of a variety of mRNAs such as chick muscle poly(A)+ mRNA, rabbit globin mRNA, EMC virus RNA, and poly(A)- and mRNA of rat liver in micrococcal nuclease-treated rabbit reticulocyte lysate. The inhibitory action of the RNA and the RNP on mRNA translation appears to involve the initiation process. The RNA and RNP do not have a nuclease activity associated with them. The hyperchromicity profile of the inhibitory RNA with increasing temperature indicates that it does not contain a significant amount of double-stranded structure. This is also supported by the complete loss of biological activity of the RNA by treatment with pancreatic RNase. In contrast, the inhibitory activity of the RNP was resistant to RNase. Electrophoresis of the protein moieties of the inhibitory RNP using both one- and two-dimensional gel techniques in the presence of sodium dodecyl sulfate shows a complex pattern of polypeptides of Mr = 12,000-150,000. The protein pattern of the 10 S particle is quite different from those of free and polysomal mRNP and poly(A)-protein complexes of chick embryonic muscles, indicating that most, if not all of the mRNA-associated proteins, are absent in the 19 S RNP. The properties of the inhibitory RNA indicate that it is different from the various low molecular weight RNA species which are involved in the modulation of protein synthesis in cell-free systems. It is concluded that the 10 S particle represents a novel class of RNP, which may be involved in posttranscriptional regulation of protein synthesis in embryonic muscles.
...
PMID:A ribonuclease-resistant cytoplasmic 10 S ribonucleoprotein of chick embryonic muscle. A potent inhibitor of cell-free protein synthesis. 611 23


<< Previous 1 2 3 4 5 Next >>

---