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)

The relationship between the antigenic proteins of Sm and RNP is not clear. To further clarify their relationship, we examined sera found monospecific by counterimmunoelectrophoresis (CIEP) for anti-Sm or anti-RNP with the more sensitive techniques of immunoblotting, radioimmunoprecipitation, or enzyme immunoassay (EIA). The same eight unique problems were precipitated by both anti-Sm and anti-RNP in radioimmunoprecipitation. They had molecular weights (MWs) of 11, 13, 17, 18, 24, 26, 28, and 68 kDa. The 17, 18, and 28 kDa bands were more intense with anti-RNP. Immunoblotting with anti-Sm and anti-RNP also recognized similar proteins with MWs of 14, 17, 25, 28, 29, 30, 36, 38, and 68 kDa. Anti-Sm resulted in more intense 14, 28, 29, and 30 kDa bands, while anti-RNP gave maximum intensity of the 14, 36, 38, and 68 kDa bands. The band intensity pattern differences were more easily appreciated with immunoblotting than with radioimmunoprecipitation. RNase, heat, and urea caused a similar diminution of antigen reactivity with both anti-Sm and anti-RNP on immunoblotting, but eliminated immunoprecipitability only of RNP on immunodiffusion. The great similarities between Sm and RNP suggest several possibilities: Anti-Sm and anti-RNP antibodies coexist in the same patients; and the more sensitive techniques of immunoblotting and radioimmunoprecipitation detect both precipitating and nonprecipitating antibodies while only precipitating antibodies are detected by immunodiffusion. Sm and RNP may represent different determinants on the same macromolecular complex. Sm and RNP may be cross-reacting determinants on distinct molecules.
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PMID:The relationship between Sm and RNP antigens. 242 69

During these last years, a powerful methodology has been developed to study the secondary and tertiary structure of RNA molecules either free or engaged in complex with proteins. This method allows to test the reactivity of every nucleotide towards chemical or enzymatic probes. The detection of the modified nucleotides and RNase cleavages can be conducted by two different paths which are oriented both by the length of the studied RNA and by the nature of the probes used. The first one uses end-labeled RNA molecule and allows to detect only scissions in the RNA chain. The second approach is based on primer extension by reverse transcriptase and detects stops of transcription at modified or cleaved nucleotides. The synthesized cDNA fragments are then sized by electrophoresis on polyacrylamide:urea gels. In this paper, the various structure probes used so far are described, and their utilization is discussed.
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PMID:Probing the structure of RNAs in solution. 244 63

The RNase-colloidal gold procedure for the ultrastructural localization of RNA was used for rat testis. Along with other structures, it was found that the testicular sperm nucleus was well stained. Similar labelling was observed in the nucleus of rat epididymal sperm and human sperm. The RNA was extracted from sperm and analyzed by electrophoresis on 10% polyacrylamide gel and 7 M urea. The electrophoretic profile revealed a complex set of bands ranging in size from tRNA to high molecular weight components. On the average, a content of about 0.1 pg of RNA per rat or human sperm was found.
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PMID:Presence of RNA in the sperm nucleus. 246 35

Only three forms of Kunjin virus-specified RNA were isolated from cytoplasm early after the latent period (about 15 hr) viz., 44 S genomic-sized single-stranded RNA, 20 S double-stranded "replicative form" (RF), and 20-28 S partially ribonuclease-resistant (about 70%) "replicative intermediate" (RI). The RF and RI were resolved by electrophoresis in aqueous-agarose gel only following LiCl fractionation. The RI did not enter urea-polyacrylamide gels. After denaturation of untreated or RNase-treated RI and RF, only 44 S RNA was present in electropherograms. RNA polymerase activity at 8 hr postinfection was detected by in vitro assays of cytoplasmic extracts and reached a maximum at 24 hr, the only major labeled product being RF; a trace amount of free 44 S RNA was also produced. These results, and the kinetics of incorporation of [3H]uridine into RI, RF, and 44 S RNA in pulse and pulse-chase experiments, formed the basis of a model in which flavivirus RF functions as a recycling template for semiconservative and (mainly) asymmetric replication, on which only one nascent strand is synthesized per cycle.
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PMID:Replication strategy of Kunjin virus: evidence for recycling role of replicative form RNA as template in semiconservative and asymmetric replication. 257 39

Partially purified RNase T2 (EC 2.7.7.17) from Aspergillus oryzae was bound through its carbohydrate moiety to Concanavalin A-Sepharose. The retention of activity was high, ranging from 70% at low enzyme load to approximately 9% at high enzyme load. Though there was no change in the pH and temperature optima, the pH stability and the Km decreased after immobilization. Compared to the soluble enzyme, the immobilized RNase T2 showed enhanced temperature stability and more resistance to metal ions. Both soluble and immobilized enzymes were stable to 8 M urea. On repeated use, the bound enzyme retained more than 60% of its initial activity after six cycles.
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PMID:Preparation and properties of RNase T2 immobilized on concanavalin A-sepharose. 259 45

A new and previously undescribed glycoprotein with a molecular weight of 43,000 has been isolated from human urine. This protein, designated GP43; copurified with ribonuclease, which has the same molecular weight, but ribonuclease activity was removed by passage through an affinity column of agarose-5'-(4-aminophenyl phosphoryl) uridine 2'(3') phosphate. GP43 contains about 5.9% neutral sugar, 2.3% hexosamine, and 1.6% sialic acid. A rabbit antibody to the purified GP43 reacted with human urine and serum as well as with the purified GP43. The genetic polymorphism of GP43 was then studied in desialylated human serum samples by urea-polyacrylamide gel isoelectric focusing, followed by immunoblotting with the specific antibody for GP43. Three common phenotypes, designated GP43 1, 1-2, and 2, were easily recognized using this technique and represented homozygosity or heterozygosity for two autosomal codominant alleles, GP43*1 and GP43/2. The frequencies of the GP43*1 and GP43*2 alleles in a Japanese population were 0.7683 and 0.2317, respectively.
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PMID:Biochemical and genetic studies on GP43, a 43-kD glycoprotein detected immunologically in human urine and serum. 262 98

The energetics of complementary packing of nonpolar side chains in the hydrophobic core of a protein were analyzed by protein engineering experiments. We have made the mutations Ile----Val, Ile----Ala, and Leu----Ala in a region of the small bacterial ribonuclease barnase where the major alpha-helix packs onto the central beta-sheet. The destabilization resulting from the creation of cavities was determined by measuring the decrease in free energy of folding from reversible denaturation induced by urea, guanidinium chloride, or heat. The different methods give consistent and reproducible results. The loss in free energy of folding for the mutant proteins is 1.0-1.6 kcal/mol per methylene group removed. This exceeds by severalfold the values obtained from model experiments of the partitioning of relevant side chains between aqueous and nonpolar solvents. Much of this discrepancy arises because two surfaces are buried when a protein folds--both the amino acid side chain in question and the portions of the protein into which it packs. These experiments directly demonstrate that the interior packing of a protein is crucial in stabilizing its three-dimensional structure: the conversion of leucine or isoleucine to alanine in the hydrophobic core loses half the net free energy of folding of barnase with a concomitant decrease in yield of the expressed recombinant protein.
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PMID:Energetics of complementary side-chain packing in a protein hydrophobic core. 266 64

RNA is shown to be covalently linked to the large tumor antigen (TAg) of simian virus 40 (SV40). Proteolytic digestion of TAg, isolated in the presence of ribonuclease inhibitors from SV40 transformed Balb/c mouse cells, generated a specific phosphopeptide of high charge heterogeneity that was strongly retained on DEAE-cellulose in the presence of 7 M urea. Hydrolysis of this peptide with RNAase released the four standard ribonucleotide monophosphates. Analysis of peptide digestion products showed that the RNA is attached to TAg through a phosphodiester linkage between the beta-hydroxyl of a serine and the 5' phosphate of an invariant cytidine residue. The methods applied to SV40 TAg can be applied to other proteins, including cellular oncogene products, to investigate the possibility of covalent protein-RNA interactions.
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PMID:RNA is covalently linked to SV40 large T antigen. 283 78

Isoelectric focusing across a concentration gradient of urea was used to study the folding-unfolding and association-dissociation processes of proteins. Myoglobulin, albumin, RNase, papain, beta L- and alpha-crystallin were analyzed with this technique, and examples are given of visualized dissociation steps and of equilibrium-unfolding intermediates. Furthermore, a two-dimensional isoelectric focusing technique is presented that is useful to deduce whether a transition of a protein aggregate observed upon urea-gradient isoelectric focusing must be attributed to a change in the protein's tertiary or quaternary structure.
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PMID:Protein folding and aggregation studied by isoelectric focusing across a urea gradient and isoelectric focusing in two dimensions. 292 18

Pregnant rats were loaded with L-phenylalanine, and the distributions of [14C]leucine and [14C]urea into fetal plasma and tissues were examined. Uptake of [14C]leucine into the supernatant and protein fractions of fetal plasma and tissues was low in the rats loaded with phenylalanine. In contrast, [14C]urea was distributed identically in both groups, indicating that maternal hyperphenylalaninemia did not affect blood flow across the placenta. Administration of phenylalanine and p-chlorophenylalanine produced amino acid imbalance in fetal tissues. Along with these changes, polysomes of the affected fetal heart and brain disaggregated without changes in the ribonuclease activity. These results indicate that high phenylalanine levels in maternal plasma disturb the active transport of amino acids across the placenta, causing an amino acid imbalance and disaggregation of polysomes in fetal heart and brain. These changes may contribute to the congenital heart disease and mental retardation of maternal phenylketonuria.
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PMID:Effects of phenylalanine loading on protein synthesis in the fetal heart and brain of rat: an experimental approach to maternal phenylketonuria. 294 18


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