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:3.1.27.4 (ribonuclease)
6,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Infectious ribonucleic acids (IRNA) of Venezuelan equine encephalitis and Eastern equine encephalitis viruses were observed to form noninfectious complexes with a basic polyamino acid, poly-l-lysine. Original infectivity was recovered from the complexes by digestion of the polylysine with Pronase, and partial recovery was effected by treatment with sodium dodecyl sulfate. Infectivity could not be recovered from the complexes containing polylysine of 100,000 molecular weight by changes in ionic strength, pH, or by treatment with phenol, deoxycholate, or digitonin. Masking of infectivity by polylysine was demonstrated in vivo as well as by plaque assay in tissue culture. Poly-l-lysine preparations of high molecular weight (44,000 to 100,000) were more effective than low molecular weight (3,000) materials in masking infectivity of IRNA. When complexes, in which infectivity had been masked by low molecular weight polylysine, were suspended in 1 m NaCl, some infectivity was recovered. Complexes of polylysine-IRNA differed from control IRNA alone in (i) resistance to inactivation by ribonuclease, (ii) sedimentation patterns in sucrose gradient centrifugation, and (iii) stability of recoverable infectivity during different physical treatments.
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PMID:Effects of poly-L-lysine on infectious viral nucleic acid. 555 81

Poly-[C]-specific ribonuclease (RNase) is released in large amounts from rat pancreas incubated at 37 degrees C in isotonic saline solution. Pancreatic cell disruption by homogenization releases only 10% of that RNase. The remainder, perhaps membrane-bound, is freed only after further membrane deterioration during anoxic incubation. Other tissues (small intestine, stomach, colon, liver, spleen, kidney, muscle, and skin) do not appear to contain much of this RNase or to release it during anoxic incubation. Relatively little amylase is released from the pancreas under the conditions that release RNase. The findings provide a rational basis for monitoring serum RNase levels in patients with acute pancreatitis for early detection and treatment of pancreatic necrosis in man.
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PMID:Release of ribonuclease from anoxic pancreas. 620 Sep 44

A CSF Poly(C)-avid ribonuclease (RNase) activity was determined in serum and CSF of 11 controls and 75 neurological patients (34 multiple sclerosis (MS), 18 infectious processes and 23 other neurological diseases (OND]. In controls, the blood-CSF ratio of RNase activity is low. This fact and the absence of correlation between serum and CSF RNase activity (except in OND group), and between CSF albumin and CSF RNase activity in controls and MS patients, suggest an intrathecal origin for the major part of this CSF RNase activity. A formula taking into account any plasmatic enrichment in RNase of the CSF is proposed to evaluate this intrathecal activity. The normal mean value of this intrathecal RNase activity is 27 +/- 3 units/ml (mean +/- SE) in our experimental conditions and using our formula. The highest intrathecal RNase activity is observed in infectious processes and this finding is associated with a significant increase in the local anti-RNA antibody synthesis. An increase in intrathecal RNase activity is rarely found in MS and local anti-RNA synthesis is only observed in one third of MS patients.
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PMID:Intrathecal origin of CSF ribonuclease. Differences between infectious processes of the nervous system and multiple sclerosis. 620 80

Activity of Poly (C) avid ribonuclease was estimated in sera of 129 patients with different malignancies. All patients had histologically verified carcinomas, normal renal function, and no signs of acute catabolic condition. Activity values were compared with those of normal subjects (U-test, Mann and Whitney) separately for each age decade and type of carcinoma. Patients with ovarian and bronchus carcinoma had statistically elevated activity values throughout all age groups. Colon carcinoma patients showed elevated values in most instances. In patients with pancreatic carcinoma a difference could be detected in only one age group (51-60 years of age). No significant elevation of enzyme activity was detected in carcinoma of the stomach and of the prostate. It is concluded that there are carcinomas leading to elevated ribonuclease activity, although the biological basis of this phenomenon is not understood. No special sensitivity nor specificity of ribonuclease elevation could be demonstrated in pancreatic carcinoma patients. Up to now the usefulness of ribonuclease estimation in prospective carcinoma detection remains questionable.
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PMID:Poly (C) avid ribonuclease estimation in patients with solid tumors. A critical evaluation. 670 20

The activity of ribonuclease (E 3.1.4.22) was estimated in sera of 401 normal subjects (normal renal function, no signs of catabolism), age ranging from 16 to 100 years (mean: 50.25 +/- 19.98) with Poly (C) as substrate. Further activity was measured with the substrates Poly (U), Poly (A) and Poly (G) in 10 sera from each age decade between 21-30 years and 81-90 years. Greatest activity was found with Poly (C) as substrate (mean: 15.88 kU/l +/- 9.57). Covariant analysis (age as covariant) revealed no sex-related activity distribution at any age, whereas the age-dependent activity increase was highly significant (p less than 0.001; 11-20 years: 9.48 kU/l +/- 3.07; 81-90 years: 34.72 kU/l +/- 5.88). Activity with the other substrates was very low and constant throughout all ages. It seems to be mandatory to consider the age of the patient when interpreting ribonuclease activity.
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PMID:Evidence of age-dependent activity increase of poly(C)-avid-serum ribonuclease in man. 720 54

The distribution of poly(adenylic acid) [poly(A)]-protein complexes in the polysomal and nonpolysomal messenger ribonucleoprotein (mRNP) fractions of Physarum polycephalum was examined in the present study. Poly-(A)-containing components released from the nonpolysomal mRNP by ribonuclease (RNase) digestion were quantitatively adsorbed to nitrocellulose filters at low ionic strength, were highly resistant to micrococcal nuclease under conditions in which free poly(A) was completely degraded, and sedimented as a 10-15S particle which was disrupted by sodium dodecyl sulfate and protease treatment. These are characteristics of the poly(A)-protein complex. In contrast,poly(A)-containing molecules released from the polysomes by RNase were refractive to nitrocellulose, were completely sensitive to micrococcal nuclease, and sedimented at 2-4 S, identical with the sedimentation exhibited by protein-free poly(A). Examination of the poly(A) sequences present in polysomal and nonpolysomal mRNP by polyacylamide gel electrophoresis showed that the former contained only very short sequences, averaging approximately 15 nucleotides, while the latter exhibited only much longer segments, averaging approximately 65 nucleotides. It is concluded that poly(A)-protein complexes are restricted to the nonpolysomal mRNP of Physarum and that the limiting factor in complex formation may be the length of the available poly(A) binding site.
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PMID:The poly(adenylic acid)-protein complex is restricted to the nonpolysomal messenger ribonucleoprotein of Physarum polycephalum. 737 86

A computer model of the complex between G2'p5'G and barnase, the recombinant ribonuclease of Bacillus amyloliquefaciens, was constructed, based on the known structure of the complex RNAase T1.G2'p5'G. This model suggests that the conserved residue Glu-60 plays an important role in the specificity of barnase for guanosine. A barnase mutant was therefore made in which Glu-60 was replaced by Gln. This mutation increases the Km for the dinucleotides GpC and GpA, by a factor of 10, but does not change the kcat. For ApA, the kcat/Km decreases by a similar factor, but the individual parameters could not be determined. The mutation, however, has no influence on the kcat and the Km of barnase action towards RNA and poly(A). This demonstrates that the interactions between the substrate and the residue at position 60 must be different in the case of ApA and poly(A). For RNA, this conclusion is also likely, but not absolutely certain, because barnase/RNA might be a Briggs-Haldane type enzyme/substrate pair. Therefore, if the effect of the mutation were limited to an increase of the dissociation rate constant of the substrate (k-1), this would not be evident in Km or kcat/Km. In view of the clear cut situation with poly(A), the pH profile for and the effect of salt concentration on the kinetic parameters of the mutant barnase were studied for this substrate. The influence of salt on the Km can be interpreted via the linked function concept and shows a cooperative dissociation of 7-10 counterions upon poly(A) binding. The binding of the substrate is strongly reduced at high pH, and the pKa involved decreases strongly at high salt concentrations. Poly(A) and RNA show a pH dependency of their absorbance spectrum, indicating a pH-dependent change of base stacking, which may influence the catalytic parameters.
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PMID:The role of Glu-60 in the specificity of the recombinant ribonuclease from Bacillus amyloliquefaciens (barnase) towards dinucleotides, poly(A) and RNA. 751 56

The degradation process of the rpsO mRNA is one of the best characterised in E coli. Two independent degradation pathways have been identified. The first one is initiated by an RNase E endonucleolytic cleavage which allows access to the transcript by polynucleotide phosphorylase and RNase II. Cleavage by RNase E gives rise to an rpsO message lacking the stabilising hairpin of the primary transcript; this truncated mRNA is then degraded exonucleolytically from its 3' terminus. This pathway might be coupled to the translation of the message. The second pathway allows degradation of polyadenylated rpsO mRNA independently of RNase II, PNPase and RNase E. The ribonucleases responsible for degradation of poly(A) mRNAs under these conditions are not known. Poly(A) tails have been proposed to facilitate the degradation of structured RNA by polynucleotide phosphorylase. In contrast, we believe that removal of poly(A) by RNase II stabilises the rpsO mRNA harbouring a 3' hairpin. In addition to these two pathways, we have identified endonucleolytic cleavages which occur only in strains deficient for both RNase E and RNase III suggesting that these two endonucleases protect the 5' leader of the mRNA from the attack of unidentified ribonuclease(s). Looping of the rpsO mRNA might explain how RNase E bound at the 5' end can cleave at a site located just upstream the hairpin of the transcription terminator.
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PMID:Multiple degradation pathways of the rpsO mRNA of Escherichia coli. RNase E interacts with the 5' and 3' extremities of the primary transcript. 891 31

A ribonuclease with a molecular weight of 29 kDa as determined by FPLC-gel filtration on Superose 12 was isolated from the sclerotia of the mushroom Pleurotus tuber-regium using a procedure involving extraction with aqueous buffer, ion exchange chromatography on DEAE-cellulose, affinity chromatography on Affi-gel blue gel, ion exchange chromatography on CM-cellulose, and FPLC on Mono S. The protein was unadsorbed on DEAE-cellulose but adsorbed on Affi-gel blue gel and CM-cellulose. It was homodimeric, made up of two identical subunits, each with a molecular weight of 14.5 kDa as witnessed in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. It exhibited potent ribonucleolytic activity toward Poly G. Its ribonucleolytic activity was resistant to heating at 100 degreesC for 30 min, but was inhibited by HgCl2, ZnSO4, NiSO4, CaCl2, and Pb(NO3)2.
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PMID:A ribonuclease from sclerotia of the edible mushroom Pleurotus tuber-regium. 978 79

From the fresh sclerotia of the mushroom Pleurotus tuber-regium, a potent homodimeric ribonuclease exhibiting a molecular weight of 29 kDa in FPLC-gel filtration and sodium dodecyl sulfate-polyacrylamide gel electrophoresis was isolated. The protein was unadsorbed on DEAE-cellulose and adsorbed on Affi-gel blue gel, CM-cellulose and Mono S. It manifested strong ribonucleolytic activity toward Poly G, slight activity toward Poly U and Poly A, and minimal activity toward Poly C. Its optimal pH was determined to be 6.5 when yeast transfer RNA was used as substrate. Its ribonucleolytic activity was resistant to heating at 100 degrees C for 30 min but was inhibited by a number of salts. The protein inhibited cell-free translation in a rabbit reticulocyte lysate with an IC50 of 0.09 nM. Three out of the four amino acid residues at the active site (positions 38-41) of P. ostreatus ribonuclease, YNNF, were also found at positions 17-20 in the P. tuber-regum RNase. However, unlike P. ostreatus RNase, no cysteine residues were detected in the N-terminal sequence.
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PMID:Purification and characterization of a potent homodimeric guanine-specific ribonuclease from fresh mushroom (Pleurotus tuber-regium) sclerotia. 1133 Dec 3


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