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

RNA was extracted from the pancreatic islets of channel catfish in the presence of the ribonuclease inhibitor, diethyl pyrocarbonate (oxydiformate). High molecular weight RNA was observed on sucrose gradient analysis. enrichment of mRNA was achieved by oligo(2'-deoxythymidylic acid)-cellulose affinity chromatography. The mRNA fraction stimulated incorporation of [35S]methionine into protein up to 30-times the background in the wheat-germ cell-free system. Analysis by sodium dodecyl sulphate-polyacrylamide gel electrophoresis revealed two major proteins corresponding to molecular weights of 27 000 and 11 000. These proteins were not observed in the absence of mRNA or in the presence of mRNAs from other tissues. They were also synthesized in the ascites tumour cell-free system. No protein co-migrating with proinsulin or insulin was detected in either the ascites or wheat-germ cell-free systems. Pancreatic islet slices also synthesized the proteins of 27 000 and 11 000 molecular weight and smaller ones as well.
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PMID:Isolation of a biologically active messenger RNA: preparation from fish pancreatic islets by oligo(2'-deoxythymidylic acid) affinity chromatography. 78 80

Bacteriophage T4-coded gene 32-protein is an essential component of the T4 replication and recombination systems. Alberts and co-workers (Alberts, B.M., Amodio, F.J., Jenkins, M., Gutmann, E.D., and Ferris, F.L. (1968) Cold Spring Harbor Symp. Quant. Biol. 33, 289-305) have shown that the major physiological activity of the protein involves preferential and cooperative binding to single-stranded DNA. In this paper, the physiochemical parameters characterizing this "melting" protein system are quantitatively determined. Boundary sedimentation velocity experiments are used to measure the interaction of gene 32-protein with native DNA. The binding is shown to be non-cooperative and involves an overlapping site size (nh) of approximately 10 nucleotide residues (or approximately 5 nucleotide pairs). In analogy with the ribonuclease results (Jensen, D.E., and von Hippel, P.H. (1976) J. Biol. Chem. 251, 7198-7214), the logarithm of the association constant (Kh) is found to be linerarly related to log [Na+]. The binding of gene 32-protein to denatured (single-stranded) DNA involves appreciable distortion of the polynucleotide backbone from the unliganded conformation; binding totally unstacks the bases of both ribose- and deoxyribose-containing polynucleotides at 10 degrees, and results in a hyperchromic change exceeding that which can be induced by heating. This hyperchromism induced in poly(dA) on binding gene 32-protein under low salt (tight binding) conditions is used to determine a value of nc (the single-stranded DNA site size) of approximately 6.7 nucldotide residues per protein. In addition, gene 32-protein binding to single-stranded polynucleotide induces an unusual circular dichroic spectrum characterized principally by a marked decrease in the magnitude of the positive CD band centered at approximately 265 nm. This spectral change is attributed to significant uncoupling of the transition moments of the vicinal bases of the single-stranded polynucleotide on gene 32-protein binding, in accord with the ultraviolet hyperchromism observed. Binding of gene 32-protein to double helical DNA has virtually no effect on the spectral properties of this conformation...
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PMID:DNA "melting" proteins. II. Effects of bacteriophage T4 gene 32-protein binding on the conformation and stability of nucleic acid structures. 79 45

Nerve growth factor (NGF) receptor binding in membrane fractions of rabbit superior cervical ganglia has been measured after treatment with a variety of enzymes, protein-modifying reagents, and ions. Receptor binding is degraded by low concentrations of trypsin but is much less sensitive to alpha-chymotrypsin. Low concentrations of phospholipase A from Vipera russelli decrease NGF receptor binding by lowering the number of binding sites, while phospholipase A preparations from Crotalus terrificus terrificus and bee venom do not affect binding. Phospholipase C and D, neuraminidase, DNase, and RNase have minimal effects on receptor binding. NGF receptor binding appears to be absolutely dependent upon calcium ion. Removal of calcium from the incubation medium greatly reduces binding as does treatment with EDTA. Maximal receptor binding occurs at 5 mM calcium. Magnesium and sodium are unable to substitute for calcium. Receptor binding is greatly reduced by treating membranes with 2-hydroxy-5-nitrobenzyl bromide, 2-methoxy-5-nitrobenzyl bromide, diazonium tetrazole, and tetranitromethane. NGF receptor sites can be protected from 2-hydroxy-5-nitrobenzyl bromide by incubation with NGF.
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PMID:Nerve growth factor receptor binding. Influence of enzymes, ions, and protein reagents. 80 4

A simple method of isolating and characterizing RNA from L-cell mitochondria is described. The mitochondrial fraction is lysed by sodium dodecyl sulphate, and the RNA fractionated by sucrose-density-gradient centrifugation. The efficacy of proteinase K in preventing ribonuclease activity is also demonstrated.
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PMID:A simple method of characterizing mitochondrial ribonucleic acid. 81 Jan 41

Cells of Bacillus subtilis heated in high concentrations of sodium dodecyl sulfate (5%) and then washed free of detergent with a hot salt solution (80 C) become structurally reorganized into regions of densely compacted cytoplasm (termed zebras) and regions of sparsely filled material (termed spaces). Size distribution studies of zebras indicate that division-suppressed mutants and wild-type cells both yield zebras of comparable length. Similarly the lengths of zebras found in populations emerging from spores are uniform in one-, two-, three-, and four-zebra-containing cells. In contrast, the length of spaces is slightly larger than that of zebras and is unusually large in two-zebra-containing cells. The locations of zebras and spaces along cell length have been studied in spore out-growth populations. A statistical procedure developed previously in genome location investigations was used to analyze the location of zebras along cell length. The data indicate that as cells elongate, new sites arise where the cell contents are strongly bound to the cell surface. Within filament populations produced by division-suppressed mutants there is a linear relationship of mean filament length and zebra number per filament. These data indicate that cytoplasm in filaments with no obvious structural compartmentalizations may be organized into units associated with particular regions of cell surface. The attachment of cell contents to the cell surface may involve deoxyribonucleic acid. Zebra-containing cells digested with proteolytic enzyme and ribonuclease are converted to cells that contain a crystalline-like granule fixed at the location of each zebra. Exposure to deoxyribonuclease mobilizes these granules within the cell wall.
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PMID:Cellular organization of Bacillus subtilis: sodium dodecyl sulfate-induced cell partitioning into zebra structures. 82 Jun 87

A fraction containing membrane-bound tobacco mosaic virus RNA replicase was isolated form tobacco mosaic virus-infected tobacco callus cultures. The replicase activity reached a maximum 60 h after inoculation and then declined. The enzyme activity was insensitive to actinomycin D and DNase. The corresponding fraction from healthy callus contained essentially no activity. The viral RNA synthesis in vitro proceeded linearly for 30 min and required the four nucleotide triphosphates and Mg2+ ions. Mn2+ was a poor substitute for Mg2+. During RNA synthesis the product was at least 70% resistant to RNase in 2X SSC (0.15 M NaCl plus 0.015 M sodium citrate), but completely digested by RNase in 0.1X SSC. Analysis of the product by polns) that appeared to be replicative form and a partially RNase-resistant structure similar to replicative intermediate form. Washing the membrane-bound replicase with Mg2+-deficient buffer solubilized enzyme. The solubulized enzyme was further purified by DEAE-Sephadex column chromatography. The DEAE-purified enzyme was nearly completely dependent upon tobacco mosaic virus RNA for activity. Analysis of the product on a sucrose gradient revealed a double-stranded RNA with sedimentation of 16S and smaller heterogeneous RNase-sensitive products.
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PMID:In vitro replication of tobacco mosaic virus RNA in tobacco callus cultures: solubilization of membrane-bound replicase and partial purification. 83 35

Total cellular RNA was isolated from the ciliate protozoan Paramecium aurelia by pH 9.5 chloroform/octanol extraction. Passage of this RNA through an oligo(dT)-cellulose column in 0.5 M NaCl resulted in 2--3% binding, indicating the presence of polyadenylic acid sequences. These polyadenylic acid regions were estimated to be 250-500 nucleotides in length, based on their resistance to ribonuclease degradation. The oligo(dT)-cellulose bound RNA sedimented at 14--25 S in sodium dodecyl sulphate/sucrose gradients. The base composition of this RNA is similar to the base composition of the DNA. This RNA was also actively translated into protein by an in vitro protein synthesizing system isolated from wheat germ. Translation was optimal under conditions similar to those used for mammalian mRNA translation. In addition, translation of the P. aurelia oligo(dT)-cellulose bound RNA was inhibited 80% by the analog 7-methylguanosine-5'-phosphate, suggesting the presence of a 5'-capped terminus.
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PMID:Isolation and characterization of mRNA from Paramecium aurelia. 88 13

Circular dichroism (CD) in the 240-300-nm region was used to study the conformation of DNA and RNA complexed with proteins in isolated nucleoli form HeLa cells. Deoxyribonuclease or ribonuclease digestion was employed to obtain (1) the individual CD spectra of nucleolar DNA or RNA in complex form with proteins, or in free form; and (2) the experimental CD baseline correction to exclude contributions from nonnucleic acid sources such as light scattering artifacts and proteins. The CD spectrum of nucleolar DNA in DNA-protein complexes was highly reduced in ellipticity in comparison with protein-free DNA. It showed a positive peak at 283 nm with a molar ellipticity [theta]283 = 1200 deg cm2 dmol-1 and a crossover at 262 nm. Addition of sodium dodecylsulfate shifted the peak to 276 nm with [theta]276 8000 deg cm2 dmol-1 and a crossover at 254 nm. The CD spectrum of nucleolar RNA in RNA-protein complexes was also reduced in comparison with protein-free RNA, showing a peak at 269 nm ([theta]269 = 6900 deg cm2 dmol-1), and a crossover at 250 nm. Addition of sodium dodecyl sulfate shifted the peak to 265 nm with [theta]265 = 18 000 deg cm2 dmol-1 and a crossover at 246 nm. The low ellipticity of both nucleolar DNA and RNA when complexed with proteins was increased by treatment with sodium chloride, urea, or heparin. This suggests that some ionic, hydrophobic, and hydrogen bondings are involved in the nucleic acid-protein interaction in nucleolar chromatin similar to that observed in nuclear chromatin.
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PMID:Circular dichroic studies of the DNA and RNA of nucleoli. 94 79

Purification of feline calicivirus was achieved by cycles of differential centrifugation and two cycles of sucrose gradient centrifugation. Feline calicivirus grown in the presence of Actinomycin D and 3H-uridine-5, sediments in 15% to 45% sucrose gradients and forms a peak of radioactivity which corresponds with the peak of infectivity. Ribonucleic acid (RNA) extracted from the peak radioactive fractions taken from the sucrose gradient sedimented as a single peak ahead of the 28S peak of cellular RNA. It was sensitive to ribonuclease and was presumed to be single stranded feline calicivirus RNA with sedimentation of 32S-35S. A single peak of radioactivity at 35S was extracted from purified virus by heating at 60 degrees for two minutes in 1% sodium dodecyl sulphate (SDS), or by heating at 37 degrees for 5 minutes at 1% SDS. Virus extracted at 37 degrees for 10 minutes in 1% SDS showed also a small peak at 16S and by 15 minutes at 37 degrees only a broad peak at 16S occurred. All peaks were susceptible to ribonuclease. A component sedimenting at 18S which was resistent to degradation by ribonuclease under the conditions outlined by Baltimore (4) and presumed to be double-stranded RNA was present in kitten kidney cells infected with feline calicivirus.
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PMID:Feline calicivirus: purification of virus and extraction and characterisation of its ribonucleic acid. 97 39

The fluorescence lifetimes and relative quantum yields of several derivatives of tyrosine are reported. The quenching of the fluorescence of these compounds by phosphate, caesium and iodide ions has been investigated; the encounter rate constants, calculated from the quenching parameters and lifetimes, show a clear dependence on the charges borne by the quenchers and fluorophores. The ratio of the Stern-Volmer constants of iodide and caesium, ions of similar size, defines an electrostatic parameter sensitive to the charge of the fluorophore which can be evaluated without knowledge of the fluorescent lifetimes. The mean of the encounter rate constants for caesium and iodide ions defines a rate constant which is largely charge-independent and is used to establish a steric parameter. The two parameters are used to investigate the tyrosine environment in bovine ribonuclease A (EC 3.1.4.23) and Erwinia carotovora L-asparaginase (EC 3.5.1.1). The quantum yield of L-asparaginase (0.12) is very high for a class A protein and may be associated with the absence of disulphide bridges. There was no evidence for more than one type of tyrosine residue from the quenching experiments with either enzyme, an observation which is attributed to efficient energy transfer amongst tyrosine residues. At pH values close to the isoelectric points of the enzymes the electrostatic parameter suggests that the environment of the quenchable tyrosines in L-asparaginase is somewhat more positive than in ribonuclease. In 1% sodium dodecyl sulphate the tyrosine environment of L-asparaginase becomes markedly negative as expected. The steric parameter indicates a lower accessibility of the tyrosine residues in L-asparaginase than in ribonuclease; an illustrative calculation is provided linking the steric parameter with the number of exposed tyrosine residues by taking into account the greater collision frequency of the larger protein molecules and the encounter distance for quenching determined from charge effects on the quenching of the model compounds. The calculation suggests that three tyrosyl residues are accessible in ribonuclease, in good agreement with other studies, but in L-asparaginase the number increases from 0.4 at pH 5.73 to 0.8 at pH 9.16 suggesting a loosening of the enzyme structure at high pH.
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PMID:An investigation of the electronic and steric environments of tyrosyl residues in ribonuclease A and Erwinia carotovora L-asparaginase through fluorescence quenching by caesium, iodide and phosphate ions. 98 70


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