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)

The efficiency of the binding of RNase 7P molecules to albumin on cocondensation with the aim of producing the prolonged action forms of the enzyme can be increased by using ligand-free human serum albumin (LFHSA). The CD method showed that LFHSA underwent changes of the cooperative character under the action of acid and urea. On potentiometric titration the number of titrated groups of LFHSA decreased with time. The GPC method demonstrated the RNase bound more efficiently to freshly dissolved LFHSA. In this case part of the enzymic activity was manifested only after proteolysis of the albumin carrier. Cocondensation with the aid of glutaraldehyde resulted in the formation of LFHSA-RNase conjugates composed of 1-2 moles of human serum albumin and 1-6 moles of RNase. More than 50% of transferase activity retained in the blood plasma for 2-3 days after intravenous injection of the conjugates with a molecular weight of 70-80 kD to rabbits.
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PMID:[Interaction of Bacillus intermedius 7P ribonuclease with ligand-free serum albumin]. 814 14

The abundance of insulin-like growth factor I (IGF-I) messenger RNA (mRNA) is decreased in the liver of fasting, protein-restricted, and energy-restricted rats. The extent to which this decrease in steady state mRNA abundance may be attributed to a decrease in IGF-I gene transcription remains unresolved. In the present study, we used an RNase protection assay to quantify IGF-I nuclear transcript (pre-mRNA) and mRNA abundance in whole cellular RNA isolated from liver of fasted and nonfasted male rats (4-6 weeks of age). The results of the RNase protection assay of IGF-I nuclear transcripts were strongly correlated with the results of nuclear transcription elongation (run-on) assays (r > 0.90; P < 0.001). In addition, the RNase protection assay allows for a greater capability for sensitively monitoring gene transcription in a large number of samples. In four different experiments, a consistent decrease in the quantity of IGF-I nuclear transcripts was observed in liver of animals fasted for 72 h, whereas IGF-I pre-mRNA abundance in animals fed ad libitum was highly variable (average intraassay coefficient of variation = 74% vs. 34% for nonfasted and fasted groups). When data from the four experiments were pooled, fasting reduced IGF-I pre-mRNA and mRNA levels by 78% and 70% (P < 0.001), respectively. Fasting also caused a significant decrease in mRNA and nuclear transcript abundance for another nutritionally sensitive gene, the gene encoding transthyretin (TTR). To determine whether the decrease in IGF-I and TTR nuclear transcripts was gene specific, levels of nuclear transcripts for serum albumin, H-ferritin, and ribosomal RNA were also quantified. The results indicated that serum albumin, H-ferritin, and ribosomal RNA nuclear transcripts were not decreased by fasting, demonstrating that the negative effect of fasting was specific for IGF-I and TTR. In summary, these results indicate that IGF-I and TTR nuclear transcripts are specifically decreased by fasting. The decrease in IGF-I mRNA is matched by a similar decrease in IGF-I nuclear transcripts, suggesting that fasting controls IGF-I gene expression primarily at the transcriptional level.
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PMID:The effect of fasting on insulin-like growth factor-I nuclear transcript abundance in rat liver. 829 71

Quantitative microcomplement fixation tests employing rabbit antisera were done to compare immunologically 13 cetacean myoglobins and 15 mammalian lysozymes c of known amino acid sequence. In both cases there was a strong correlation between immunological distance (y) and percent sequence difference (x), as had been found for several other globular proteins. For myoglobin the relationship could be described by y = 10.5x and for lysozyme by y = 8.5x. The coefficients in both of these equations are appreciably higher than the values of 5.1-6.9 reported for three other vertebrate globular proteins (bird lysozyme c, mammalian ribonuclease, and mammalian serum albumin), and they imply that rabbit antisera to mammalian myoglobins and lysozymes are more sensitive to evolutionary substitutions. A strong inverse correlation (r = -0.95) was found when the slope of the line relating y to x for these five data sets was plotted against the percent sequence difference between the rabbit's own protein and the proteins immunized with. Specifically, the cetacean myoglobins on average differ in amino acid sequence from rabbit myoglobin by less than 13% and exhibit the steepest slope (10.5), while bird lysozyme sequences differ by nearly 40% from rabbit lysozyme and exhibit the shallowest slope (5.1).
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PMID:The sequence-immunology correlation revisited: data for cetacean myoglobins and mammalian lysozymes. 830 8

Changes in biological properties of serum albumin, egg white lysozyme, human serum alpha-1 antiproteinase and human leukocyte ribonuclease in effect of interaction with the enzyme system composed of myeloperoxidase from human neutrophilic polymorphonuclear leukocytes, Cl- and H2O2 were investigated. All the studied proteins lost their biological functions and were denaturated, but the amounts of hydrogen peroxide necessary to produce these effects differed remarkably for each individual protein. The alpha-1 antiproteinase ability of binding to trypsin was abolished upon employing 1.2 mols of H2O2 per mol of alpha-1 antiproteinase. The lysozyme enzymatic activity was abolished when 1.4 mols of H2O2 per mol of lysozyme were employed. Albumin decreased its binding to specific antialbumin antibodies and entirely lost the binding properties when 2 mols and about 10 mols of H2O2 per mol of albumin were employed, respectively. On the other hand 18 mols of H2O2 per mol of human leukocyte ribonuclease were necessary to inactivate this enzyme. All the mentioned proteins were protected from losing their biological functions by excess of specific amino acids with affinity to hypochlorite: Alpha-1 antiproteinase by excess of N-acetylmethionine, lysozyme by N-acetylmethionine and N-acetyl glycyltryptophane, albumin by N-acetyl derivatives of methionine, cysteine, tryptophane and lysine, whereas ribonuclease was protected from denaturation by all above mentioned amino acid derivatives. None of the studied proteins was protected from denaturation by N-acetyl tyrosine, or phenylalanine.
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PMID:Inactivation and denaturation of some proteins by enzyme system: myeloperoxidase, chloride and hydrogen peroxide. 840 71

The binding efficiency of high affinity monoclonal antifluorescyl antibody 4.4-20 with the homologous ligand situated in different protein environments has been investigated to quantitate the effect of non-active site secondary factors. To synthesize monofluoresceinated proteins, fluorescein 5-isothiocyanate was reacted with a 100-fold molar excess of ribonuclease, lysozyme, lactalbumin and bovine serum albumin. Absorption and emission spectra, as well as fluorescence life-time measurements which yielded discrete components and proteolytic studies suggested that fluorescein was conjugated to a specific lysine residue consistent with a non-random distribution of lysines within each protein population. The derivatized residue was probably a surface moiety based on accessibility analyses with iodide as a dynamic quencher. Dissociation rate analyses indicated that the relative release time of 4.4-20 with each monofluoresceinated protein was Fl-RNAse > or = Fl-lyso > or = FDS > Fl-lact > or = Fl-BSA which correlated with changes in free energy of binding. Relative fluorescence quenching measurements of the fluorescein moiety indicated that 4.4-20 showed decreasing quenching in the order FDS > Fl-RNAse > Fl-lyso > or = Fl-lact > Fl-BSA. Because spectral data indicated that fluorescein was conjugated to a specific residue or a non-random distribution of residues in each protein population, the results represented the effect of a single distinct environment or a weighted average of different microenvironments. Results have been interpreted within the theoretical framework of a dynamic antibody model involving conformer selection and the relative effects of primary and secondary interactions.
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PMID:Effects of secondary forces on the primary antibody-ligand interaction. 855 47

Estrogen-mediated accumulation of the avian apolipoprotein (apo) II mRNA is in part due to its stabilization. To identify the biochemical activity responsible for this effect, radiolabeled, capped, and polyadenylated apoII mRNA was incubated in vitro in liver cytosolic extracts from roosters who received either estrogen (estrogen-treated extract) or the vehicle (control extract) parenterally. The mRNA was very stable in estrogen-treated extract but was rapidly degraded in control extract. The RNA was degraded predominantly by endonuclease rather than exonuclease activity. The addition of the estrogen-treated extract to the control extract prevented the degradation of the mRNA in trans. This biochemical activity was heat labile and was also destroyed by proteinase K but not by micrococcal nuclease, indicating that estrogen treatment resulted in the expression of a protein in the liver that stabilized the apoII mRNA by inhibiting its nucleolytic degradation. This mRNA stabilization factor was labile around 60 degrees C, whereas the RNase remained stable up to 80 degrees C. Studies on mRNA protein interaction showed that both control and estrogen-treated extracts contain mRNA-binding (mRNP) proteins that bind apoII mRNA. An increased binding to apoII mRNA by a subset of these proteins was observed with estrogen-treated extract as compared with the control extract. This activity, although it afforded complete protection from nucleolytic degradation to apoII and apo A1 mRNAs, appeared to provide less protection to mRNAs encoding chicken serum albumin and vitellogenin, suggesting differential stabilization of mRNAs. These studies indicate that a cytosolic mRNA-stabilization factor, providing apoII mRNA complete protection from nucleolytic degradation, is expressed in the avian liver upon estrogen treatment. This appears to be the first time that a biochemical activity responsible for hormone-mediated stabilization of mRNAs and estrogen induction of mRNA binding by specific mRNPs have been identified and partially characterized in vitro.
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PMID:In vitro characterization of an estrogen-regulated mRNA stabilizing activity in the avian liver. 877 38

The equilibrium partition coefficient (K) and diffusion coefficient (Dgel) of two proteins and two linear polymers were measured as a function of polymer content of a 2.7% cross-linked polyacrylamide (PA) gel. The gel concentration, expressed as a volume percentage of PA in the gel (phi), varied between 0 and 14%. The measurements were made by fluorescence spectroscopy; fluorescent dyes were covalently attached to the macromolecules. The dependence of K on phi for the proteins agrees with a model of the gel network as randomly placed, impenetrable rods. The diffusion data are interpreted in terms of an effective medium theory for the mobility of a sphere in a Brinkman fluid. Using values of the Brinkman parameter in the literature, the effective medium model with no adjustable parameters fits the diffusion data for the proteins very well but underpredicts Dgel for the linear polymers. The gel effect on partitioning is significantly greater than that on diffusion. The permeability (KDgel) of bovine serum albumin decreased by 10(3) over the range phi = 0 --> 8%, and the ratio of permeabilities for ribonuclease compared to BSA increased from 2 to 30.
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PMID:Partitioning and diffusion of proteins and linear polymers in polyacrylamide gels. 1120 65

During purification of fungal deoxyribonuclease (DNase) from Syncephalastrum racemosum, a protein which was functionally unknown and persistently existed in the DNase-containing fractions through chromatography over DEAE-cellulose, hydroxylapatite, and phenyl-Sepharose was identified. The protein was finally separated from DNase after affinity chromatography on a cibacron blue-Sepharose column and purified to apparent homogeneity after gel chromatography on a Superdex 200 HR column. Ten tryptic peptides of this protein were isolated and sequenced. Searching in the sequence data bank with the aid of the computer program PC/Gene, we found that this protein was highly homologous to aspartic proteinases, such as pepsin and rhizopuspepsin. Because of its fungal origin and because the protein indeed showed catalytic cleavage on peptide bonds of bovine serum albumin, RNase, and carbonic anhydrase, we termed this protein syncephapepsin. The molecular weight of syncephapepsin is 38,000 daltons, based on gel filtration and sodium dodecyl sulfate-polyacrylamide electrophoresis.
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PMID:Identification of a fungal protein of Syncephalastrum racemosum as aspartic proteinase. 883 44

Some cysteine-containing proteins upon sulfitolysis have been found to show anomalously retarded SDS-PAGE mobilities in non-reducing gels. These proteins include bovine serum albumin, ovalbumin, aldolase, ribonuclease and a recombinant fusion protein (XA) consisting of a portion of gamma-interferon linked to the A chain of human insulin. This mobility shift has been employed to determine the stability of the sulfonated products and to study the kinetics of the sulfitolysis reaction. Partially sulfonated products of intermediate shifts were observed at 0.01% beta-ME, while 0.05% beta-ME gave a shift characteristic of the completely reduced protein. The undiluted sulfitolysis reagent reacted with XA to give within 1 min a gel shift characteristic of the fully sulfitolysed protein. Its transition stages could be visualized at 15, 30 and 60 min when the reagent was diluted four-fold. In the presence of 8 M urea, the sulfitolysis of BSA was nearly complete at 30 min when the sulfitolysis reagent was used at a dilution of 1:5. However, under the same conditions BSA was predominantly unsulfitolysed in the absence of urea. In order to elucidate the mechanism of sulfonation shift, several derivatives of XA, e.g. performic acid oxidized, alkylated with (a) iodoacetamide and (b) iodoacetate, have been prepared. While the mobility of XASSO3- was sensitive to the presence of beta-ME, all other derivatives moved in a beta-ME-insensitive fashion. Furthermore, while the nonreducing mobilities of the acidic derivatives (-SSO3-, -SO3- and -SCH2CO2-) were anomalously retarded and identical, the mobility of the iodoacetamide derivative was intermediate between the retarded acidic derivatives above and XA below. These studies have suggested a role of the extended conformation of the A chain of insulin in causing a mobility shift of the acidic derivatives in this series. Similar results were observed in an analogous series of derivatives prepared from BSA. Non-denaturing gel filtration analyses of native vs. sulfitolysed samples of serum albumin, ovalbumin and ribonuclease have indicated that the sulfitolysed proteins elute earlier than their native counterparts and appear to be significantly larger than their true molecular weights. Circular dichroism analysis has indicated significant loss in helicity of sulfitolysed BSA. This suggests that the retarded mobility of sulfitolysed proteins seen on SDS-PAGE is likely to be due to an expansion in the hydrodynamic volumes of these proteins, a phenomenon triggered by cleavage of disulfide bonds and further accentuated by the introduction of strongly negatively charged sulfonates.
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PMID:Anomalous mobility of sulfitolysed proteins in SDS-PAGE. Analysis and applications. 889 91

Temperature dependencies of 1H non-selective NMR T1 and T2 relaxation times measured at two resonance frequencies and natural abundance 13C NMR relaxation times T1 and T1r measured at room temperature have been studied in a set of dry and wet solid proteins - Bacterial RNase, lysozyme and Bovine serum albumin (BSA). The proton and carbon data were interpreted in terms of a model supposing three kinds of internal motions in a protein. These are rotation of the methyl protons around the axis of symmetry of the methyl group, and fast and slow oscillations of all atoms. The correlation times of these motions in solid state are found around 10(-11), 10(-9) and 10(-6)s, respectively. All kinds of motion are characterized by the inhomogeneous distribution of the correlation times. The protein dehydration affects only the slow internal motion. The amplitude of the slow motion obtained from the carbon data is substantially less than that obtained from the proton data. This difference can be explained by taking into account different relative inter- and intra- chemical group contributions to the proton and carbon second moments. The comparison of the solid state and solution proton relaxation data showed that the internal protein dynamics in these states is different: the slow motion seems to be few orders of magnitude faster in solution.
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PMID:Dynamic structure of proteins in solid state. 1H and 13C NMR relaxation study. 891 57


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