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)

All purified preparations of the ribosome-inactivating proteins ricin A, phytolaccin and Shiga toxin were shown to exhibit ribonuclease activity with 5S or 5.8S rRNA substrates. These toxin species generated reproducible patterns of RNA fragments distinct for each toxin species while multiple preparations of a single toxin species yielded similar RNA fragment patterns. The heat inactivation profile of Shiga toxin was identical for its RNase and protein synthesis inhibitory activities. These data are the first to indicate that the ribosome-inactivating catalytic toxins, in addition to alpha-sarcin, exhibit RNase activity. These results suggest RNase activity may be responsible for ribosome-inactivation catalyzed by ricin, phytolaccin and Shiga toxin proteins.
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PMID:Ribonuclease activity associated with the 60S ribosome-inactivating proteins ricin A, phytolaccin and Shiga toxin. 383 73

The carboxyl group in a ribonuclease from Rhizopus sp. (RNase Rh) was modified by a water-soluble carbodiimide, 1-cyclohexyl-3-(2-morpholinyl-(4)-ethyl)carbodiimide p-toluenesulfonate (CMC). From the relation between the extent of modification and the enzymatic activity, it was concluded that at least the modification of two carboxyl groups seemed to induce the loss in enzymatic activity. In the presence of 1 M cytidine, RNase Rh activity was protected from the CMC-modification. Under conditions in which the enzyme was inactivated to 20% activity, about 70% of the enzymatic activity was retained in the presence of cytidine. The inactivation of the RNase Rh pre-treated with CMC in the presence of cytidine with [14C]CMC indicated that the RNase Rh lost its enzymatic activity with the incorporation of about one [14C]CMC. Therefore, it could be concluded that one carboxyl group is involved in the active site of RNase Rh. The binding of the CMC-modified RNase Rh with 2'-AMP was studied spectrophotometrically. The affinity of the modified RNase Rh towards 2'-AMP decreased markedly upon CMC modification.
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PMID:Modification of a ribonuclease from Rhizopus sp. with 1-cyclohexyl-3-(2-morpholinyl-(4)-ethyl)carbodiimide p-toluenesulfonate. 386 65

RNase T, a nuclease thought to be involved in end-turnover of tRNA, has been purified about 4,000-fold from extracts of Escherichia coli. At this stage of purification, the enzyme was judged to be at least 95% pure based on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The native molecular weight of RNase T determined from gel filtration and sedimentation analyses is about 50,000, whereas the monomer molecular weight determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis is 25,000, suggesting that the protein is an alpha 2 dimer. Purified RNase T is extremely sensitive to inactivation by oxidation, sulfhydryl group reagents, and temperature. The ribonuclease activity against tRNA-C-C-[14C]A is optimal at pH 8-9 in the presence of 2-5 mM MgCl2 and ionic strengths of less than 50mM. Although RNase T is highly specific for intact tRNA-C-C-A as a substrate and can hydrolyze all species in a mixed population of tRNA, it is inhibited by other RNAs, such as poly(A), rRNA, 5 S RNA, and tRNA-C-C. RNase T is an exoribonuclease which initiates attack at a free 3' terminus of tRNA and releases AMP; aminoacyl-tRNA is not a substrate. The role of RNase T in the end-turnover of tRNA and its possible involvement in other aspects of RNA metabolism are discussed.
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PMID:Purification and characterization of Escherichia coli RNase T. 388 94

A ribonuclease that preferentially cleaves natural and synthetic double-stranded (ds) RNAs has been partially purified from Pennisetum typhoides. The enzyme degrades [3H]poly(rA) X poly(rU) to acid-soluble products. The ds RNase does not degrade RNA:DNA hybrid but appears to have about 18% activity against single-stranded (ss) RNAs under the assay conditions used for the cleavage of ds RNAs. The RNase has a molecular weight of 35,000 daltons as determined from gel filtration using Sephadex G-200. The ds RNase shows an absolute requirement for divalent cations Mg++ or Mn++ and monovalent cations K+ or Na+. The specificity of the enzyme towards ds RNA template is supported by the inhibition of cleavage of ds RNAs by ethidium bromide and Penicillium chrysogenum viral ds RNA. The enzyme preparation acts on ds RNAs isolated from Saccharomyces cerevisiae and P. chrysogenum virus. The purified ds RNase also cleaves the in vitro transcriptional products of adenovirus DNA and this activity is inhibited by 5 mM ethidium bromide suggesting that ds regions of adenovirus RNA are involved in the cleavage process.
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PMID:Action of Pennisetum typhoides double-stranded ribonuclease on viral ds RNAs. 391 48

A fully active semisynthetic ribonuclease, RNase 1-118:111-124, may be prepared by enzymatically removing six residues from the COOH terminus of the protein (positions 119-124) and then complementing the inactive RNase 1-118 with a chemically synthesized peptide containing the COOH-terminal 14 residues of the molecule (RNase 111-124) [M. C. Lin, B. Gutte, S. Moore, and R. B. Merrifield (1970) J. Biol. Chem. 245, 5169-5170]. Nitration of tyrosine-115 in the peptide followed by complex formation with RNase 1-118 affords a fully active enzyme containing a unique nitrotyrosine residue in a position which is known and which is very likely to be completely exterior to the active site region. The binding constant between the tetradecapeptide and RNase 1-118 (5 X 10(6) M-1 at pH 6.0) is not changed by the nitration. Crystals of the nitrated complex are isomorphous with those of RNase 1-118:111-124, for which a refined 1.8-A structure has recently been obtained.
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PMID:A semisynthetic bovine pancreatic ribonuclease containing a unique nitrotyrosine residue. 402 12

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.
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PMID:Extensive symmetrical transcription of Simian Virus 40 DNA in virus-yielding cells. 434 93

The antispermatogenic effect of seminal ribonuclease BS-1 was studied by injecting the substance intratesticularly, intraperitoneally, or subcutaneously in white mice. Selective damage was noted in 63% of seminal tubules after doses of 20 mcg (intratesticular) and in almost all the tubules after 50 mcg. Subcutaneous injections of 1.5 and 2.5 mg produced damage to 74% and 80% of the tubules, respectively, and intraperitoneal injections of 200 and 500 mcg produced damage to 35% and 88% of the tubules, respectively. RNase A and physiologic saline injections had no deleterious effect on any tubules in 20 animals. Examination of the liver, kidney, heart, spleen, skin, small intestine, bone marrow, and lung tissues of RNase BS-1 treated mice revealed no damage to any of these tissues. These results suggest that RNase BS-1 possesses a specific antispermatogenic effect in mice.
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PMID:[Anti-spermatogenic effect of seminal ribonuclease (BS-1 RNase)]. 437 1

The distribution of ribosomal protein binding sites on the 16S ribosomal RNA molecule has been analyzed by limited ribonuclease hydrolysis of RNA-protein complexes, as well as by the interaction of individual proteins with RNA fragments purified from partial enzymatic digests. Of the six 30S subunit proteins known to interact directly with 16S RNA, proteins S4, S8, S15, S20, and, probably, S13 bind within a fragment produced by T(1) RNase (12S RNA) that comprises some 900 nucleotides and covers almost the entire 5'-terminal half of the 16S molecule. A fragment of 500-600 nucleotides (8S RNA) that is contiguous with 12S RNA and arises from the 3'-terminal portion of the 16S molecule is believed to contain the binding site for protein S7. Protein S15 interacts specifically with a sequence of about 135 nucleotides (4S RNA) that derives from 12S RNA after more extensive hydrolysis. Protein S4, but none of the other ribosomal proteins, binds to a 500-nucleotide fragment (9S RNA), generated by pancreatic RNase, that lies at the 5'-terminus of 16S RNA and is completely overlapped by the 12S fragment. A preliminary map of the binding sites is presented.
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PMID:Location of ribosomal protein binding sites on 16S ribosomal RNA. 455 59

A material inhibiting antibody synthesis in vitro is produced during the productive phase by rabbit lymph node organ cultures undergoing a secondary response. This antibody inhibitory material (AIM) has been isolated from serum-free medium taken from the cultures and also extracted from lymph node fragments as late as their 4th wk in vitro. AIM inhibits most strikingly the early productive phase of the secondary response in vitro (i.e, during the 2nd wk). AIM isolated from cultures undergoing a given immune response inhibits the same as well as different responses, thus indicating an immunologically nonspecific effect. Ultrafiltration and related studies reveal that the molecular size of AIM is 10,000-50,000 daltons and that it is not antibody. AIM can readily be separated from 7S globulin by use of CM-cellulose. The inhibitory activity of AIM is lost by digestion with ribonuclease. Thus the avoidance of serum with its high levels of ribonucleases may be crucial in the study of this material. The presence in eukaryotic cells of metabolic regulators, governors, etc. has been postulated largely by analogy with microbial systems (27). There is little direct evidence about the chemical nature of these presumed regulators. Our data on the RNase sensitivity of AIM raises the possibility in this lymphoid system of regulation by a species of RNA.
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PMID:Regulation of the secondary antibody response in vitro. II. Chemical properties of an antibody inhibitory material (AIM) produced in antigen-stimulated rabbit lymph node organ culture. 470 67

Assays of ribonuclease activity in components of mature and immature mammalian erythroid cells indicate that RNase activity is present both in the membrane-free hemolysate and the washed membranes. Erythroid cell RNase exists in an active and latent form. The majority of total cell RNase activity is in the latent state, and is localized to the erythroid cell membrane. Both total and latent RNase activity decline as the cell matures. The latent RNase is released from its relatively firm attachment to the cell membrane and activated by centrifugation or, optimally, by exposure to 4 M urea. The active sites of membrane-associated RNase are apparently oriented toward the inner side of the cell membrane. The properties of the latent membrane-bound RNase which is activated by urea, including K(m), pH optimum, inhibition of enzyme activity by cations, and response to metabolic inhibitors, do not differ significantly from those of the soluble RNase in the membrane-free hemolysate, suggesting that there is only one type of RNase in the erythroid cell. Binding of Rnase to the erythroid cell membrane stabilized the enzyme against inactivation during incubation at 37 degrees C, and the findings suggest that membrane-bound RNase may play a particular part in degrading ribosomes. The findings indicate that the cell membrane has a major role in RNA metabolism in the maturing mammalian erythroid cell.
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PMID:Erythroid cell RNase: activation by urea and localization to the cell membrane. 554 82


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