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:3.1.26.9 (ribonuclease)
6,589 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To assess whether myoglobin adversely affects renal adenylate pools, rats were infused with purified myoglobin (50 mg/100 g body wt) for two hours and renal ATP, ADP, and AMP levels were measured in the absence of shock, after 25 minutes of hemorrhagic shock (55 to 60 mm Hg) or 30 minutes post-recovery. In the absence of shock, myoglobin lowered ATP by 24% (assessed 65 min post-infusion) without affecting renal blood flow (RBF). This effect was completely blocked by deferoxamine (DFO) treatment and it could not be reproduced by ribonuclease infusion (a non-Fe containing, but filtered, protein). Myoglobin + shock caused a three- to fourfold greater decline in ATP than did shock alone despite comparable RBFs. Shock plus myoglobin, but neither one alone, induced substantial S1/S2 proximal tubular morphologic damage and a severe reduction in creatinine clearance, confirming synergistic injury. Ribonuclease completely reproduced myoglobin's effect on shock-induced adenylate profiles. DFO +/- hydroxyl radical scavenger therapy (Na benzoate) did not block the myoglobin shock effect on adenylate pools. Post-shock adenylate recovery was not compromised by myoglobin pre-treatment. If renal artery occlusion (RAO), rather than shock, was used as the ischemic challenge, myoglobin had no discernible impact on adenine nucleotide content. This study concludes that: 1) myoglobin modestly lowers baseline adenylate pools due to an Fe dependent mechanism; 2) myoglobin drastically accentuates shock-induced adenylate depletion by a non-hemodynamic/non-Fe dependent mechanism; 3) myoglobin nephrotoxicity cannot be attributed solely to tissue iron loading; and 4) the RAO model can completely mask important influences on ischemic cellular energetics.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Myoglobin depletes renal adenine nucleotide pools in the presence and absence of shock. 200 25

Ribonuclease T1 and the mutant enzymes were cocrystallized with several ribonucleotides, including non-hydrolyzable substrate analogs of di- and triribonucleotides, which have a novel guanylate in which the 2'-hydroxyl group of the ribose is replaced by a fluorine atom. One of the mutant enzymes has a tryptophan residue, instead of Tyr45 of the wild-type enzyme, to enhance the binding of ribonucleotides to the enzyme and the other mutant enzyme has histidine and aspartate residues, instead of Asn43 and Asn44, respectively, to reproduce the natural substitutions found in ribonuclease Ms. Polymorphism of the crystals was observed for wild-type and mutant enzymes. However, orthorhombic crystals, which are virtually all isomorphous to each other, were successfully obtained from wild-type and mutant (Y45W) enzymes by the macroscopic seeding technique using mother crystals of the wild-type ribonuclease T1 complexed with 2'GMP or 3'GMP. The diffraction patterns of these crystals extend beyond 2.5 A resolution and the diffraction data were collected from some of the crystals on a diffractometer up to a range of 2.5 to 1.8 A resolution.
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PMID:Crystallographic characterization of wild-type and mutant ribonuclease T1 complexes with several ribonucleotides. 208 29

Ribonuclease activity in HeLa cell nuclei is markedly inhibited by ADP-ribosylation following incubation of intact isolated nuclei with [14C]NAD. Time course experiments demonstrate that [14C] incorporation into proteins is accompanied by a 50% inhibition of ribonuclease activity on single-strand and double-strand polynucleotides. Inhibition does not occur when 3-aminobenzamide, a potent (ADP-ribose) polymerase inhibitor, is present. Two enzymatic activities that degrade double-strand polynucleotides have been purified and partially characterized. A relevant level of radioactivity resulting from [14C]NAD incubation of nuclei was associated to the purified enzyme. The RNase F1 component, which shows maximal activity on polyU-polyA is demonstrated to be the major ADP-ribose acceptor protein.
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PMID:In vitro inhibition of HeLa cell nuclear ribonucleases by ADP-ribosylation. 211 91

Increasing the flexibility of a protein enhances its susceptibility to defined proteases in vitro. To ascertain whether flexibility also affects protein stability in vivo, radioiodinated proteins with similar structures, but dissimilar flexibilities, were introduced into HeLa cells using red cell-mediated microinjection. Intracellular proteolysis was then measured as the rate of release of 125I-tyrosine into the medium. Ribonuclease A was considerably more resistant to degradation by purified proteases or in reticulocyte lysate than its flexible derivatives ribonuclease S and S-protein. In contrast, all three proteins were equally stable within HeLa cells. Like the results obtained for RNases, the rates of degradation of trypsin inhibitors, trypsin analogs, and their complexes correlated with flexibility in reticulocyte lysate. However, the intracellular half-lives of anhydrotrypsin and various proteinaceous trypsin inhibitors were not affected upon formation of enzyme-inhibitor complexes. Furthermore, trypsinogen was degraded more slowly than the structurally similar anhydrotrypsin in HeLa cells, although trypsinogen has additional segmental flexibility in its activation domain. Electrophoretic analyses revealed that trypsin-inhibitor complexes remained intact following injection into HeLa cells, and that neither free inhibitors nor anhydrotrypsin formed Triton-stable complexes with soluble cytoplasmic proteins. The observation that the components of the trypsin-inhibitor complexes were degraded simultaneously indicates that neither constituent unfolded prior to the onset of proteolysis. These studies provide evidence that RNases, trypsin, and trypsin inhibitors are degraded by an intracellular proteolytic pathway(s) which recognizes surface features of the folded proteins.
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PMID:Degradation of proteins microinjected into HeLa cells. The role of substrate flexibility. 243 Sep 58

Though the substantial part of serum ribonuclease (EC 3.1.27.5) is of pancreatic origin, there are no consistent data on changes in activity of serum alkaline ribonuclease in acute pancreatitis. The recent findings suggest that the increase in ribonuclease activity refers only to patients with necrotic outcome of acute pancreatitis. The aim of this study was to reevaluate the suggestion that elevated ribonuclease activity is specifically related to pancreatic necrosis. Our studies included 57 patients with verified acute pancreatitis, and 11 patients evolving haemorrhagic or necrotic lesions of the pancreas. It was found, that the enzyme increasing in some percentage of patients with acute pancreatitis is the Poly-C avid "pancreatic" ribonuclease. This enzyme begins to increase in the 2nd or third day after onset of the disease, always after decrease in serum amylase activity down to levels close to normal range. Ribonuclease activity increased up to days 5 or 6 of the disease, and then decreased along with diminution of disease symptoms upon treatment. Correlation studies showed that increased ribonuclease activity in acute pancreatitis is related to a higher than the 2nd degree of severity of the clinical course of the disease, to pancreatic necrosis, death, diminished glomerular filtration rate, and age. Thus, pancreatic necrosis is not the exclusive factor directing the increased ribonuclease activity in acute pancreatitis, but the increased ribonuclease activity seems to be a late marker of acute pancreatitis of a severe clinical course.
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PMID:Determination of ribonuclease activity in serum of patients with pancreatic necrosis. An attempt of extending the enzyme diagnosis of acute pancreatitis. 261 34

We have used the technique of ribonuclease protection to define genomic variation among circulating isolates of subgroup A respiratory syncytial (RS) virus. RNAs extracted from HEp-2 cells infected with strains to be analyzed were hybridized with a 32P-labeled RNA probe corresponding to the RS virus G glycoprotein (A2 strain). Areas of nonhomology were detected by cleavage with ribonuclease A. Using this technique, multiple distinct RNA cleavage patterns could be distinguished among viral isolates recovered from infants residing in the same metropolitan area and infected during the same epidemic season. Epidemiologically related isolates (from coinfected twins, from infants infected during a nosocomial outbreak at an extended care facility, and from institutionalized adults infected during an outbreak) yielded identical patterns. In two separate outbreaks, differences in cleavage patterns among certain isolates corresponded to epidemiologically significant differences among the individuals from whom the isolates were recovered. We conclude that substantial genomic heterogeneity exists among circulating isolates of subgroup A RS virus. Ribonuclease protection can be used as a molecular fingerprinting tool for expanded studies of the molecular epidemiology of this virus.
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PMID:RNA fingerprinting of respiratory syncytial virus using ribonuclease protection. Application to molecular epidemiology. 272 64

Alkaline phosphatase (ALP) in human choriocarcinoma cells (malignant trophoblasts) was characterized by its greater sensitivity to EDTA and L-leucine inhibition as compared with the placental isozyme. In addition, both the fully processed and the nonglycosylated forms of choriocarcinoma ALP migrated faster than the corresponding placental enzyme in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Choriocarcinoma cells express a 2.6-kilobase (kb) ALP mRNA unlike normal human placenta which expresses a 2.8-kb ALP mRNA. Administration of sodium butyrate to choriocarcinoma cells greatly increased the steady-state levels of the 2.6-kb choriocarcinoma ALP mRNA, which resulted in an increase in enzyme activity and biosynthesis. S1 nuclease analysis using probes derived from a placental ALP cDNA and ribonuclease protection assays employing probes derived from the germ cell ALP gene demonstrated that choriocarcinoma cells express the germ cell ALP gene. The germ cell ALP gene encodes the placental ALP-like isozyme that is primarily expressed in the thymus, testis, and germ cell tumors. The structures of the internal exons (II-X) of the germ cell ALP gene were determined previously based on their similarity to the placental ALP gene. However, the boundaries of exons I and XI (3' exon) of the germ cell ALP gene were not defined due to sequence divergence between the two genes at the 5' and 3' regions. Ribonuclease protection and primer extension assays demonstrated that exon I of this gene is 119 base pairs in length and that germ cell ALP mRNA contains one major transcription initiation site. The isolation and characterization of germ cell ALP cDNA clones from a butyrate-treated choriocarcinoma cDNA library showed that the germ cell ALP mRNA is 2487 bases in length and exon XI of this gene is 1135 base pairs long.
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PMID:Expression of the germ cell alkaline phosphatase gene in human choriocarcinoma cells. 274 60

This report presents a technique for recovery of mouse forebrain proteins from two-dimensional sodium dodecyl sulfate-polyacrylamide gels for subsequent primary structure determination. Proteins were visualized by Coomassie staining or salt precipitation and manually cut out of the gel. Excised spots were minced and loaded into an empty precolumn of a reversed-phase high-performance liquid chromatography system. Purified protein was extruded from a gel matrix by pressurized liquid, then separated from gel contaminants by reversed-phase gradient elution, and finally collected in siliconized tubes or on polybrene-coated filter disks for gas-phase sequencing. Several mouse and rat forebrain proteins were purified by this method and sequenced. Three previously unidentified mouse brain proteins with molecular weights of 4,000, 12,000, and 18,500 were partially sequenced and three hemoglobin fragments were structurally identified and mapped. Ribonuclease A, myoglobin, adrenocorticotropin, and bovine somatotropin were also subjected to two-dimensional (2-D) analysis and partially sequenced. Recovery values of 27-95% were obtained for extruded 14C-labeled ribonuclease, carbonic anhydrase, and bovine serum albumin out of sodium dodecyl sulfate-polyacrylamide gel electrophoretic gels. Losses resulting from the multiple handling steps of a 2-D gel separation process were also investigated. Recoveries of 12-17%, as determined by sequencing signals, were achieved. These latter recovery values reflect overall losses incurred in gel-focusing, gel-sizing, staining, destaining, high-pressure liquid extrusion, and N-terminal blockage. This work demonstrates that an array of protein spots can be systematically identified or defined by partial sequencing after high-pressure liquid extrusion from a 2-D gel matrix.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Isolation and sequence analysis of proteins from mouse forebrain using two-dimensional gel electrophoresis coupled to high-pressure liquid extrusion. 281 64

The diagnostical relevance of the low-molecular proteins ribonuclease, beta 2-microglobulin and lysozyme in serum and urine to detect a reduced glomerular filtration rate was examined in 52 patients with chronic renal diseases. The radioisotope clearance using 99mTc-DTPA was the base reference; the reference values of the low-molecular proteins were estimated in a control group. Ribonuclease was increased above the upper borderline value, if the glomerular filtration rate was lower than 1.24 ml s-1. Creatinine, beta 2-microglobulin and lysozyme remain yet in part in the normal range. The estimation of the ribonuclease in serum is suitable to detect an impaired glomerular filtration rate if the creatinine value is still not increased. Thereby, the diagnostics in renal diseases may be improved in the creatinine-blind area.
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PMID:[The low molecular weight proteins ribonuclease, beta 2 microglobulin and lysozyme in the serum and urine of patients with chronic kidney diseases]. 307 Oct 37

Using automated Edman degradation of two nonfractionated peptide mixtures of tryptic and staphylococcal protease digests of the protein, the complete amino acid sequence of the guanyl-specific ribonuclease Sa from Streptomyces aureofaciens was established. Ribonuclease Sa contains 96 amino acid residues (Mr 10,566). A 50% sequence homology of ribonuclease Sa to the guanyl-specific ribonuclease St from S. erythreus was found.
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PMID:Amino acid sequence determination of guanyl-specific ribonuclease Sa from Streptomyces aureofaciens. 309 82


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