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)

1. Nitrogen retention was determined by classical N balance techniques in fourteen rapidly growing low-birth-weight infants receiving 3 g protein/kg body-weight and during their 3rd week of life. This was compared with plasma free alkaline ribonuclease (EC 3.I.4.22; RNase) activity and other biochemical measurements of protein nutrition. 2. Plasma RNase showed a significant positive correlation with N retention and a corresponding negative correlation with urine urea-N. These results were unexpected and suggest a different relationship between RNase and N retention in infants compared with that found by other workers in children and adults. 3. The most likely explanation of this apparent anomaly is that in all instances high activities of plasma RNase are associated with a need to conserve N. In the infants studied this may indicate some measure of 'protein economy' and they could therefore benefit from a higher protein intake.
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PMID:Plasma alkaline ribonuclease (EC 3.1.4.22) and nitrogen retention in low-birth-weight infants. 71 28

We have recently shown that 16S RNA can be extracted from 30S ribosomes by an acetic acid-urea precipitation procedure which yields RNA capable of binding 13 individual ribosomal proteins. This is in contrast to phenol extracted 16S RNA which can specifically associate with only 7 proteins2-7. In the experiments reported here, we demonstrate that the difference in protein binding capacities is due to a relatiely more "open" configuration possessed by the acetic acid-urea 16S RNA. Under identical conditions, acetic acid-urea 16S RNA is more susceptible to limited T1-RNase digestion than is phenol-16S RNA. In addition, acetic acid-urea RNA shows a relatively slower electrophoretic mobility. The observable difference in conformation between the two types of RNA is lost by storage at-70 degrees C. This loss is accompanied by a reduction in protein binding capacity of the acetic acid-urea 16S RNA.
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PMID:Evidence that 16S RNA from E. coli can assume two different biologically active conformations. 78 27

Purified influenza virus contains ribonuclease activity. The enzyme does not hydrolyze viral RNA but both 28 S and 18 S host cell RNA are degraded forming large (about 16 S) and small (about 5 S) fragments with the release of the acid-soluble material. It has an optimum temperature of 37 degrees C, requires no divalent ions, and is inhibited by 0.1 M EDTA and 1% SDS. Treatment with 4 M urea increases enzymatic activity considerably (42%) but is not a prerequisite for eliciting ribonuclease activity suggesting that the enzyme is probably located near the surface of the virus particle. Results show that the observed enzyme activity is virus-associated as no host cell protein is detectable in the purified virus.
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PMID:Association of a ribonuclease with the purified influenza virus. 81 84

The cells of Escherichia coli strain CP 78 were labeled with [32P]orthophosphate and the total radioactive RNA was prepared from the cells. The mRNA that codes for a structural lipoprotein in the outer membrane was purified from the total RNA by three successive electrophoreses on polyacrylamide slab gels, twice at pH 8.3 and once at pH 3.5 in 7 M urea. Approximately 0.002% of the total radioactive phosphate used was incorporated into the fraction containing the most purified mRNA. The two-dimensional fingerprint of the T1 ribonuclease digest of the 32P-labeled mRNA showed that the purity of the mRNA was as high as 90%. A preliminary sequence analysis was carried out on the T1 ribonuclease oligonucleotides which had been separated by the fingerprinting procedure. By using the established amino acid sequence of the lipoprotein and the genetic code, three relatively long oligonucleotides were assigned to code for three different parts of the lipoprotein. From these data, the present RNA fraction was identified as the lipoprotein mRNA. From the analysis of the T1 ribonuclease oligonucleotides, the mRNA was estimated to be 360 +/- 10 nucleotides in length. Although the length of the mRNA was enough to code for 2 lipoprotein molecules, T1 ribonuclease digestion of the mRNA yielded only 1 mol/mol of mRNA of the individual oligonucleotides assigned to parts of the amino acid sequence of the lipoprotein. This suggests that the mRNA codes for only 1 molecule of the lipoprotein. It was also found that the mRNA has no polyadenylate sequence at the 3' end.
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PMID:Isolation and identification of the messenger ribonucleic acid for a structural lipoprotein of the Escherichia coli outer membrane. 82 86

Two general methods for the isolation of DNA from various sources based on the use of cetyltrimethylammonium bromide (cetavlon, CTA-Br) are described. Cetavlon is a strong cationic detergent precipitating DNA from diluted salt solutions. Cells are lysed and cellular components are dissolved in the presence of cetavlon, 5 M urea, 0.1 M EDTA and 2 M NaCl (KCl). In the first method pure DNA is precipitated in the form of CTA-salt by direct dilution of the lysate to bring the concentration of NaCl (KCl) down to 0.5 M after the removal of the main part of proteins by deproteinization with chloroform. In the first method pure DNA is precipitated in the form of CTA-salt by direct dilution of the lysate to bring the concentration of NaCl (KCl) down to 0.5 M after the removal of the main part of proteins by deproteinization with chloroform. In the second method DNA is purified on the hydroxyapatite column after cell lysis and the removal of cell debris by centrifugation. Both methods are suitable for rapid isolation of pure DNA from various sources with recovery about 80% and average molecular weight 20-10(6) and higher without use of ribonuclease, pronase and amylase.
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PMID:[Two simple methods for isolation of DNA from various sources using cetavlon]. 92 66

The effects of a combination of an alcohol and urea on the transition temperature of bovine ribonuclease were investigated. The combined effects on the transition temperature of ribonuclease of a polyvalent alcohol and urea are about equal to the algebraic sum of the effects of each individual additive. The effects of a monovalent alcohol and urea are not cummulative, especially not at low temperatures (30 degrees C). The presence of urea decreases the hydrophobic effect of a monovalent alcohol, strongly at low temperatures, to a lesser degree at high temperatures (60 degrees C). Consequently, urea hinders the interhydrophobic interactions by affecting the water molecules.
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PMID:The effects from combining urea and an alcohol on the heat-induced reversible denaturation of ribonuclease. 94 44

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

32P- and methyl-3H-labeled 70S Moloney murine leukemia virus RNA was purified from virions produced in Moloney murine leukemia virus-infected mouse embryo cells. Primer-free RNA subunits obtained by heat treatment and zonal centrifugation were digested with RNase T2, and methylated oligonucleotides were chromatographed on DEAE-Sephadex in 7 M urea. Approximately one molecule of RNase T2-stable oligonucleotide (-5 charge) was isolated per subunit. Structural analysis indicated that the sequence of the oligonucleotide is m7GpppGmpCp. Analysis of the mononucleotide fraction isolated by DEAE-Sephadex chromatography of the RNase T2 digest identified 15 to 23 internal N6-methyladenylic acid molecules per subunit.
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PMID:Methylation pattern of genomic RNA from Moloney murine leukemia virus. 97 37

The methylated constituents of early adenovirus 2 mRNA were studied. RNA was isolated from polyribosomes of cells double labeled with [methyl-3H]methionine and 32PO4 from 2 to 7 g postinfection in the presence of cycloheximide. Cycloheximide ensures that methylation and processing are performed by preexisting host cell enzymes. RNA was fractionated into polyadenylic [poly(A)]+ and poly(A)- molecules using poly(U)-Sepharose, and undergraded virus-specific RNA was isolated by hybridization to viral DNA in 50% formamide at 37 degrees C. Viral mRNA was digested with RNase T2 and chromatographed on DEAE-Sephadex in 7 M urea. Two 3H-labeled RNase T2-resistant oligonucleotide fractions with charges between -5 and -6 were obtained, consistent with two classes of 5' terminal methyl "cap" structures, m7G(5')ppp(5')NmpNp (cap 1) and m7G(5')ppp(5')NmNmpNp (cap 2) (Nm is a ribose 2'-O-methylation). The putative cap 1 contains all the methylated constituents of cap 1 plus Cm. The molar ratios of m7G to 2'-O-methylnucleosides is about 1.0 for cap 1 and 0.5 for cap 2, consistent with the proposed cap structures. Most significant, compositional analysis indicates four different cap 1 structures and at least three different cap 2 structures. Thus there is a minimum of seven early viral mRNA species with different cap structures, unless each type of mRNA can have more than one 5' terminus. In addition to methylated caps, early mRNA contains internal base methylations, exclusively as m6A, as shown by analyses of the mononucleotide (-2 charge) fraction. m6A was present in the ratio of 1 mol of m6Ap per 450 nucleotides. Thus viral mRNA molecules contain two to three internal m6A residues per methyl cap, since there is on the average 1 cap per 1,250 nucleotides.
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PMID:Multiple methylated cap sequences in adenovirus type 2 early mRNA. 97 98

A major cell surface protein, CSP, of chick embryo fibroblasts has been shown to constitute up to 3% of total cell protein, and to be decreased after viral transformation. Its role in normal cell behavior is not known. We have isolated CSP from chick embryo fibroblasts by extraction with 1 M urea and find that these preparations of CSP agglutinate formalinized sheep erythrocytes at protein concentrations of under 2 mug/ml. In extracts of chick embryo cells, the quantity of such hemagglutinating activity parallels that of CSP determined by electrophoresis, and both are substantially decreased in chick cells transformed by the Bryan hightiter strain of Rous sarcoma virus. Both CSP and hemagglutinating activity are progressively adsorbed onto erythrocytes and can be released by 1 M urea. An antiserum to purified CSP specifically blocks the agglutination. The agglutinating activity is destroyed by boiling or treatment with proteases. The agglutination reaction is inhibited by the chelating agents EDTA and EGTA [ethyleneglycol-bis(beta-aminoethyl ether)N,N'-tetraacetic acid]. Agglutination is also inhibited to a lesser degres by amino sugars and other amines, increased osmolarity, and urea. Other monosaccharides, hyaluronidase, DNase, and RNase have little or not effect on the agglutination reaction. This demonstration that CSP has an agglutinating activity that is sensitive to proteases and that requires divalent cations suggests that this molecule may play a role in cell adhesion.
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PMID:The major cell surface glycoprotein of chick embryo fibroblasts is an agglutinin. 105 2


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