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)

Rat brain extracts contain two heat-stable, nondialyzable inhibitors of tubulinyl-tyrosine carboxypeptidase. One of the inhibitors was sensitive to ribonuclease and insensitive to trypsin and pronase, indicating that the inhibitor is RNA. This is supported by the observation that purified RNA from rat brain inhibited the enzyme activity to the same extent as similar amounts of the endogenous RNA. Similar results were obtained with calf liver RNA. The other inhibitor was purified by chromatography on a DEAE-Sephadex and identified as proteoglycan. The elimination of the protein moiety of the proteoglycan resulted in a small increase of its inhibitory activity. Glycosaminoglycan was released from the proteoglycan by beta elimination, indicating that the linkage between glycosaminoglycan and the protein moiety is through an O-glycosidic bond. The glycosaminoglycan contains uronic acid, hexosamine and sulfate in a molar ratio of 1:1.01:0.99, respectively. Treatment of the glycosaminoglycan with chondroitinase ABC completely abolished its inhibitory activity. Chondroitin sulfate A, chondroitin sulfate B, chondroitin sulfate C, and the brain glycosaminoglycan inhibited tubulinyl-tyrosine carboxypeptidase to the same extent when used in comparable amounts.
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PMID:Inhibition of tubulinyl-tyrosine carboxypeptidase by brain soluble RNA and proteoglycan. 616 Nov 29

A base-specific ribonuclease (RNase) Ru (EC 3.1.27.5) was isolated and purified from Rhizopus niveus in a yield of 17% by the procedures of acetone precipitation, column chromatography on Duolite A-2, DEAE-cellulose, CM-cellulose, and 2'(3')-aminohexyl-5'-UMP-agarose. The enzyme was shown to be homogeneous by polyacrylamide disc electrophoresis. The amino- and carboxyl-terminal amino acids of the enzyme were determined to be an arginine and an aspartic acid, respectively. The enzyme has a base specificity: it released only 3'-UMP from yeast RNA or poly(U) and, in addition, small amounts of 3'-CMP from poly(C).
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PMID:Purification of a base-specific ribonuclease Ru from Rhizopus niveus. 616 47

The interaction of the 1 alpha,25-dihydroxyvitamin D3 receptor with immobilized calf thymus DNA has been compared with its sedimentation properties on hypotonic sucrose gradients. Forty to sixty percent of total hormone:receptor complexes formed at 4 degrees C were retained by DNA-cellulose and could be eluted by 0.18 to 0.2 M KCl. In contrast, heating preparations to 25 degrees C rapidly and irreversibly converted receptor to a form which bound hormone and DEAE-cellulose normally, but was unable to associate with DNA. Similarly, the ability of receptor to aggregate to a 6 S species was labile at 25 degrees C. Stabilization of receptor in the DNA binding aggregating form was accomplished using Ca2+, Mg2+, Mn2+, or Na2MoO4 while several protease and phosphatase inhibitors were ineffective. An examination of DNA binding properties of aggregating and nonaggregating receptor forms revealed that only receptor competent to enter into aggregates could bind DNA suggesting that a functional nucleic acid binding site, and, hence, a nucleic acid interaction is necessary for aggregate formation. Consistent with this view, an RNA:receptor interaction appears to be involved in formation of the 6 S complex since removal of RNA by ribonuclease treatment or purification of receptor reduced aggregation, an effect that could be reversed by addition of purified RNA.
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PMID:Temperature-dependent inactivation of nucleic acid binding and aggregation of the 1,25-dihydroxyvitamin D3 receptor. 618 53

A specific binding site for somatotropin was solubilized by 1% (v/v) Triton X-100 from a crude particulate membrane fraction of pregnant rabbit liver, partially purified and characterized. The solubilized binding site retained many of the characteristics observed in the original particulate fraction, indicating that extraction of the binding site with Triton X-100 does not cause any major changes in its properties. The binding of human 125I-labelled-somatotropin to the solubilized binding site is a saturable and reversible process, depending on temperature, incubation time, pH and ionic environment. Analysis of the kinetic data revealed a finite number of binding sites with an affinity constant of 0.32 x 10(10)M-1. The binding activity for human 125I-labelled-somatotropin was adsorbed to a concanavalin-A-Sepharose column and was dissociated from the column with alpha-methyl-D-glucoside, suggesting that the binding protein may be a glycoprotein. Using affinity chromatography on concanavalin-A-Sepharose, ion-exchange chromatography on DEAE-cellulose and gel filtration on Sepharose 6B, the binding protein was purified 1000-4000-fold from the original liver homogenate. When the partially purified preparation was chromatographed on Sepharose 6B, the binding protein eluted as a molecule with an apparent molecular weight of 200000, with a Stokes' radius of 4.9 nm. Sucrose-density-gradient centrifugation of the preparation showed that the sedimentation coefficient of the binding protein was 7.2S. Isoelectric focusing experiments revealed that a major part of the protein has an acidic pI (4.2-4.5). Exposure of the protein to trypsin decreased the binding activity for human 125I-labelled-somatotropin or bovine 125I-labelled-somatotropin, whereas ribonuclease, deoxyribonuclease, phospholipase C or neuraminidase had little or no effect.
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PMID:Characteristics of solubilized human-somatotropin-binding protein from the liver of pregnant rabbits. 624 70

The effect of various treatments on the activity of anti-treponemal lymphotoxin (ATL) produced by lymphocytes of syphilitic rabbits was studied. Treponema pallidum-killing activity of ATL was slightly reduced after heating at 56 degrees C and completely abolished at 100 degrees C. The significant reduction of the activity was also obtained after exposure of ATL to acidic conditions (pH 1-5) at room temperature, or by treatment with papain and neuraminidase. Activity of ATL was completely resistant to deoxyribonuclease, ribonuclease and trypsin treatment. ATL was eluted from the Sephadex G-100 column together with hemoglobin, that suggested the apparent molecular weight of ATL of about 65,000. The active fraction from the Sephadex G-100 column was further fractionated on DEAE-Sephadex A-50. The activity of ATL was widely spread in the column eluate, indicating the charge heterogeneity. All these data indicate that ATL is a relatively low molecular weight protein. The sensitivity to neuraminidase and heterogeneity of charge suggest that it is a glycosylated protein.
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PMID:Characterization of anti-treponemal lymphotoxin from lymphocytes of syphilitic rabbits. 638 57

A nuclear p53/55 protein kinase has been isolated from nuclear ribonucleoprotein particles from human tumor cells. The enzyme was purified approximately 2200-fold cell nuclei by sequential ribonuclease digestion of the RNP particles, DEAE cellulose and phosphocellulose chromatography. The kinase which was cAMP independent, catalyzed the phosphorylation of rabbit muscle glycogen synthase in the amino terminal domain, and conversion of the I to D form. The D synthase had a phosphorylation stoichiometry of 8 moles 32P per mole of synthase subunit with maximal specificity for ATP as phosphate donor; its Km was 30 microM. An antinucleolar antibody inhibited enzyme activity by 80%. Substrates for most other kinases were inactive. The kinase was essentially unaffected by the Walsh inhibitor, EGTA, regulatory subunits of protein kinase, calmodulin, trifluoperazine or heparin. Its activity was lost at 1 mM polyamine, but was enhanced 3-fold by MnCl2 and 4- to 9-fold by deoxymononucleotides. The nuclei of HeLa cells contained 64% of the total kinase of which 64% of the total kinase of which 11% were in nucleoli; the specific activity of the nucleolar kinase was twice that of the nuclear supernatant and four times that of the cytoplasmic kinase. These results indicate that nucleolar ribonucleoprotein particles of human tumor cells contain a cAMP-independent protein kinase which is similar to glycogen synthase kinase.
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PMID:Purification of p53/55 kinase from nuclear ribonucleoproteins of Namalwa cells. 643 81

Ribonuclease F1, the guanine-specific ribonuclease of Fusarium moniliforme, was purified to homogeneity by a combination of ethanol fractionation, affinity chromatography and DEAE-cellulose column chromatography. The adsorbent for the affinity chromatography was synthesized by the coupling of periodate-oxidized guanosine 5'-monophosphate to aminohexyl agarose followed by sodium borohydride reduction. Ribonuclease F2, the minor component, was also purified to near homogeneity by the same procedure. Ribonucleases F1 and F2 had the same molecular weight (about 11,000) as determined by gel filtration and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. They also showed the same amino acid composition and differed only in the isoelectric point: 4.10 for F1 and 3.96 for F2.
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PMID:Purification by affinity chromatography and physicochemical properties of the guanine-specific ribonuclease of Fusarium moniliforme. 678 May 47

Total HeLa cell extract was separated into multiple components using first DEAE-Sephadex and then phosphocellulose column chromatography. Four major fractions, DE175, DE500, P100, and P1000, from HeLa cells are found to be essential for accurate and efficient transcription of cloned ovalbumin DNA fragments in the reconstituted system. DE175 serves as the source for RNA polymerase II and DE500 minimizes the synthesis of small molecular size RNA. P100 enhances the levels of specific transcription, while P1000 is absolutely required for correct initiation. Chick oviduct crude extract was also fractionated into multiple components according to the same procedure. Similar efficiency of specific initiation could be obtained when an individual fraction (DE175, DE500, P100, or P1000) from oviduct cells was exchanged for a fraction from HeLa cells. These results indicate that chick oviduct tissue also contains general transcription factors like that of HeLa cells and these factors can be fractionated according to the same procedure. In this fractionation scheme, we were able to separate the bulk of RNase activity into the P350 fraction which was not required for initiation of ovalbumin RNA transcription. Thus, this reconstituted system is suitable for studying in vitro transcription in a homologous system derived from tissue extracts, even though a substantial amount of cellular ribonuclease may be associated with it.
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PMID:Transcription factors from oviduct and HeLa cells are similar. 689 17

The aminoacylation of rat liver tRNA with selenocysteine was studied in tissue slices and in a cell-free system with [75Se]selenocysteine and [75Se]selenite as substrates. [75Se]Selenocysteyl tRNA was isolated via phenol extraction, 1 M NaCl extraction and chromatography on DEAE-cellulose. [75Se]Selenocysteyl tRNA was purified on columns of DEAE-Sephacel, benzoylated DEAE-cellulose and Sepharose 4B. In a dual-label aminoacylation with [35S]cysteine, the most highly purified 75Se-fractions were greater than 100-fold purified relative to 35S. These fractions contained less than 0.7% of the [35S]cysteine originally present in the total tRNA. When [35Se]selenocysteyl tRNA was purified from a mixture of 14C-labeled amino acids, over 97% of the [14C]aminoacyl tRNA was removed. The [75Se]selenocysteine was associated with the tRNA via an aminoacyl linkage. Criteria used for identification included alkaline hydrolysis and recovery of [75Se]selenocysteine, reaction with hydroxylamine and recovery of [75Se]selenocysteyl hydroxamic acid and release of 75Se by ribonuclease. The specificity of [75Se]selenocysteine aminoacylation was demonstrated by resistance to competition by a 125-fold molar excess of either unlabeled cysteine or a mixture of the other 19 amino acids in the cell-free selenocysteine aminoacylation system.
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PMID:Identification of a selenocysteine-specific aminoacyl transfer RNA from rat liver. 692 51

Circulating M antigen, specific for genus Schistosoma, was previously described in serum, urine, patients' milk, and in serum and urine of animals infected by S. mansoni. The M antigen was thermostable and soluble in trichloroacetic acid. It was not hydrolyzed by protease, ribonuclease, amylase, or neuraminidase but destroyed by sodium metaperiodate. In the present study, we have purified the M ag by using trichloroacetic acid solubility, DEAE Sephadex, and immunoadsorption. The M ag showed a neutral electric charge, a m.w. heterogeneity, and was only stained by periodic acid-Schiff. The composition study revealed M ag was a glycoprotein with a polysaccharide moiety (63% of the molecules) particularly rich in galactose, fucose, glucosamine, and mannose, and with a high molecular ratio of serine and threonine. The presence of O-glycosidic linkage allowed M ag to be considered as a mucin or a mucus glycoprotein-like component. It was localized in the cell wall of the gut of adult worms.
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PMID:Purification, immunochemical, and biologic characterization of the Schistosoma circulating M antigen. 698 17


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