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)

In the 5'-flanking region of the bovine pancreatic ribonuclease gene a sequence has been identified which specifically binds one or more factors present in nuclear protein extracts prepared from bovine pancreas. The binding site, as delineated by footprinting analysis, is located in a region extending from positions -113 to -146 relative to the transcription initiation site of the ribonuclease gene. This region contains consensus sequences for known control transcriptional elements. The observed pattern of protein-DNA interactions is likely to be pancreas-specific as it could not be detected with nuclear extracts prepared from HeLa or bovine aorta endothelium cells.
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PMID:Protein-DNA interactions in the 5'-flanking region of the bovine pancreatic ribonuclease gene. 133 97

A process for conformational modification of protein, which we have previously reported, was investigated as a means of generating fluorohydrolase activity in bovine ribonuclease (RNase). The resulting modified RNase had catalytic activity that depended upon the chosen modifier. Bovine pancreatic ribonuclease, modified by addition of hexamethylphosphoramide (HMPA) at pH 3, was derivatized with diimidates of chain lengths from C1 to C8. The derivative with the highest activity was obtained when RNase was crosslinked with dimethyl pimelimidate (C5). This derivative, which was active over a pH range of 6.5 to 8.0 with an optimum pH of 7.4, hydrolyzed phenylmethylsulfonylfluoride (PMSF) and the potent acetylcholinesterase inhibitor, diisopropyl phosphorofluoridate (DFP). The mean fluorohydrolase activity for four preparations using dimethyl pimelimidate was 0.8 +/- 0.2 U mg-1. Gel filtration on G-75 Sephadex and SDS-polyacrylamide gel electrophoresis showed components having a molecular weight of 13,000 and 27,000, with activity restricted to the 27,000 molecular weight fraction. After gel filtration, the specific activity was 9.1 +/- 2.4 U mg-1, resulting in a molecular activity of 125 min-1. The mechanism of this unique transformation of RNase into a fluorohydrolase is not known, nor has the location of the active site been determined.
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PMID:Semisynthetic fluorohydrolases prepared by chemical modification of ribonuclease. 136 89

The crystal structure of ribonuclease A with bound thymidylic acid tetramer is reported at 2.5-A resolution. The diffusion of the tetramer into native orthorhombic crystals of the ribonuclease allows for the formation of a structurally stable complex where the single-stranded nucleic acid enters and leaves the enzyme's catalytic region in a persistent 5'-3' direction. The binding of the tetramer to the enzyme's surface is facilitated and mediated by electrostatic interactions between basic protein residues and nucleotide phosphates. Two pyrimidine nucleotides are bound to the enzyme's active site in a manner similar to that observed for other complexes between ribonuclease A and nucleic acid oligomers.
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PMID:Crystal structure disposition of thymidylic acid tetramer in complex with ribonuclease A. 142 75

The coding sequence for the bovine pancreatic ribonuclease (RNase) precursor has been cloned and produced in Escherichia coli using the polymerase chain reaction (PCR) technique. A PCR amplification has been carried out utilizing as template the recombinant plasmid, pQR138, which contains the coding sequence for the RNase precursor, and primers that allow for the addition of new sequences at the 5' and 3' ends of the coding sequence. The resultant fragment contains two coding sequences, one for a hexapeptide and the other for pre-RNase. This fragment has been cloned into the expression vector, pKK223.3, under the control of the tac promoter, to form a two-cistron vector. Upon induction with IPTG, E. coli cells harboring this construct generate a bicistronic mRNA which upon translation produces a hexapeptide and pre-RNase. The RNase precursor is efficiently translocated into the periplasmic space of E. coli. Upon translocation, the signal sequence is removed generating mature RNase. Formation of the disulfide bridges in RNase is facilitated by the oxidative environment of the periplasm and a fully active protein is obtained. RNase produced in E. coli has been purified to homogeneity by cation-exchange chromatography, and the removal of the signal sequence has been verified by N-terminal sequencing. The total process from inoculation of media to obtaining pure and fully active recombinant RNase is achieved in 48 h.
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PMID:Production of mature bovine pancreatic ribonuclease in Escherichia coli. 151 98

In an earlier study we found that different forms of the v-myb oncogene transform myeloid cells which resemble either monoblasts [when v-myb of avian myeloblastosis virus (AMV) was used] or promyelocytes [when a point mutant in v-myb of AMV was used; Introna, M., Golay, J., Frampton J., Nakano, T., Ness, S.A. & Graf, T. (1990). Cell, 63, 1287-1297]. In the present study we have searched for genes expressed in AMV mutant-transformed promyelocytes that are not expressed in AMV-transformed monoblasts using a differential screening approach. Eight different genes were identified among more than 500 differentially expressed clones. The most abundant of these was the previously identified myb-regulated mim-1 gene. The others were found to encode a small calcium-binding (MRP-like) protein; the p20K protein; goose-type lysozyme; a ribonuclease A/angiogenin-related protein; and three non-identified proteins. Although these genes appear to be rather lineage restricted, their expression varied in different subtypes of transformed myelomonocytic cells, and only two of them (goose lysozyme and ribonuclease) showed a similar expression pattern in normal promyelocytes and macrophages, suggesting an aberrant gene regulation in the transformed cells. Co-transfection experiments of a reporter construct containing the promoter of the ribonuclease A-related gene indicated that this promoter is regulated by the v-Myb oncoprotein without the involvement of Myb-specific binding sequences.
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PMID:Identification of genes differentially expressed in two types of v-myb-transformed avian myelomonocytic cells. 154 65

Thioredoxin (Trx) from Escherichia coli was compared with bovine protein disulfide-isomerase (PDI) for its ability to catalyze native disulfide formation in either reduced or randomly oxidized (scrambled) ribonuclease A (RNase). On a molar basis, a 100-fold higher concentration of Trx than of PDI was required to give the same rate of native disulfide formation measured as recovery of RNase activity. A Pro-34 to His (P34H Trx) mutation in the active site of E. coli Trx (WCGPC), mimicking the two suggested active sites in PDI (WCGHC), increased the catalytic activity in disulfide formation about 10-fold. The mutant P34H Trx displayed a 35-mV higher redox potential (E'0) of the active site disulfide/dithiol relative to wild type Trx, making it more similar to the redox potential observed for PDI. This higher redox potential correlates well with the enhanced activity and suggests a role for the histidine side chain. Enzymatic isomerization of disulfides in scrambled, oxidized RNase requires the presence of a catalytic thiol such as GSH to initiate the thiol-disulfide interchange. Bovine thioredoxin reductase, together with NADPH, could replace GSH. For oxidative folding of reduced RNase in air with Trx, P34H Trx, or PDI, catalytic amounts of sodium selenite (1 microM) resulted in rapid disulfide formation and high yields of ribonuclease activity equivalent to previously known redox buffers of GSH and GSSG. These results demonstrate no obligatory role for glutathione in disulfide formation. A possible mechanism for the unknown thiol oxidative process accompanying folding and protein disulfide formation in vivo is discussed.
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PMID:A Pro to His mutation in active site of thioredoxin increases its disulfide-isomerase activity 10-fold. New refolding systems for reduced or randomly oxidized ribonuclease. 157 42

The primary structure of the blood vessel inducing protein angiogenin is 35% identical with that of pancreatic ribonuclease (RNase) and contains counterparts for the critical RNase active-site residues His-12, Lys-41, and His-119. Although angiogenin is a ribonucleolytic enzyme, its activity toward conventional substrates is lower than that of pancreatic RNase by several orders of magnitude. Comparison of the amino acid sequences of RNase and angiogenin reveals several striking differences in the region flanking the active-site lysine, including a deletion and a transposition of aspartic acid and proline residues. In order to examine how these sequence changes alter the functional properties of angiogenin, an angiogenin/RNase hybrid protein (ARH-II), in which residues 38-41 of angiogenin (Pro-Cys-Lys-Asp) have been replaced by the corresponding segment of bovine pancreatic RNase (Asp-Arg-Cys-Lys-Pro), was prepared by regional mutagenesis. Compared to angiogenin, ARH-II has markedly diminished angiogenic activity on the chick embryo chorioallantoic membrane but 5-75-fold greater enzymatic activity toward a variety of polynucleotide and dinucleotide substrates. In addition, the specificity of ARH-II toward dinucleotide substrates differs from that of angiogenin and is qualitatively similar to that of pancreatic RNase. Thus, non-active-site residues near Lys-40 in angiogenin appear to play a significant role in determining enzymatic specificity and reactivity as well as angiogenic potency. An additional angiogenin/RNase hybrid protein (ARH-IV), in which residues 59-71 of ARH-II have been replaced by the corresponding segment of pancreatic RNase, was also prepared.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Mutagenesis of residues flanking Lys-40 enhances the enzymatic activity and reduces the angiogenic potency of angiogenin. 169 54

Variations in urinary kallikrein in pancreatic diseases were ascertained, and possible influencing factors were investigated. Serum amylase and urinary excretion of glandular kallikrein, pancreatic ribonuclease (RNase), gamma-glutamyltransferase (GGT) and amylase were measured in 24 control subjects, 39 patients with pancreatic cancer, 49 with pancreatitis and 63 with extra-pancreatic diseases. Urinary kallikrein was found to be elevated in a substantial number of patients with pancreatitis. Higher levels were detected in patients with a relapse, which was diagnosed using clinical and biochemical examinations. RNase was also increased in a high number of patients with pancreatic diseases, but was not correlated with pancreatic damage. In patients with pancreatitis, a correlation was found between urinary kallikrein and RNase excretions. No correlations were found between kallikrein and serum or urinary amylase and GGT. We can conclude that urinary kallikrein excretion increases in pancreatitis, especially when a phlogistic involvement of the pancreas is present; this condition may lead to a release of this ultrafiltrable enzyme in the circulation. Renal tubular damage, which determines a reduced reabsorption of this enzyme, seems to play a concomitant but minor role in this process.
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PMID:Urinary kallikrein excretion in chronic pancreatic diseases. 172 73

Two fragments of pancreatic ribonuclease A, a truncated version of S-peptide (residues 1-15) and S-protein (residues 21-124), combine to give a catalytically active complex designated ribonuclease S. We have substituted the wild-type residue Met-13 with six other hydrophobic residues ranging in size from alanine to phenylalanine and have determined the thermodynamic parameters associated with binding of these analogues to S-protein by titration calorimetry in the temperature range 5-25 degrees C. The heat capacity change (delta Cp) associated with binding was obtained from a global analysis of the temperature dependences of the free energies and enthalpies of binding. The delta Cp's were not correlated in any simple fashion with the nonpolar surface area (delta Anp) buried upon binding.
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PMID:Heat capacity changes for protein-peptide interactions in the ribonuclease S system. 173 99

In this paper we report the molecular cloning of the gene encoding the bovine brain ribonuclease. The nucleotide sequence determined in this work shows a high degree of identity to the homologous gene encoding the bovine pancreatic ribonuclease. Processing of the primary transcripts of these genes also follows a similar pathway, splicing of the unique intron in the 5' untranslated region occurs at corresponding positions. Expression of the bovine brain ribonuclease gene can be detected both at the transcriptional and translational levels in all the regions of the brain examined.
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PMID:Molecular cloning of the gene encoding the bovine brain ribonuclease and its expression in different regions of the brain. 175 84


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