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:3.1.27.5 (RNase)
17,967 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A number of "surface" enzymes of Escherichia coli (i.e., among those selectively released by osmotic shock) all displayed higher specific activities in extracts of minicells than in extracts of typical rod forms; these enzymes included alkaline phosphatase, cyclic phosphodiesterase, acid hexose monophosphatase, 5'-nucleotidase, and ribonuclease I. In addition, alkaline phosphatase, cyclic phosphodiesterase, and acid hexose monophosphatase were cytochemically localized to regions of minicell periplasm that resembled reactive polar enlargements of the periplasm in rod forms. In contrast, a number of "internal" cytoplasmic enzymes (inorganic pyrophosphatase, beta-galactosidase, glutamine synthetase, polynucleotide phosphorylase, and ribonuclease II) showed elevated or similar specific activities in extracts of rod forms versus extracts of minicells. A specific heat-labile inhibitor for 5'-nucleotidase, known to occur in the cytoplasm, also showed no enrichment in minicells. These findings indicate that the "surface" enzymes are segregated in vivo into the terminal minicell buds, possibly because these enzymes are concentrated in the polar enlargements of the periplasm in typical rod forms.
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PMID:Biochemical and cytochemical evidence for the polar concentration of periplasmic enzymes in a "minicell" strain of Escherichia coli. 431 25

A pool of alkaline phosphatase subunits has been found in cells of Escherichia coli which are actively synthesizing the enzyme. The radioactive subunits from pulse-labeled cells were specifically recognized by their capacity to produce, upon incubation with Zn(++) and nonradioactive monomers, radioactive dimers with the characteristics of alkaline phosphatase. The pool of subunits was larger (10 times or more) than the amount expected to be bound to ribosomes and was bound to a rapidly sedimentable fraction from which 60% was released by ribonuclease. In a culture pulse-labeled for one-third (8 sec) of the enzyme synthetic time, the pool of radioactive monomers was 81% of the radioactive enzyme and was totally (98%) in the endoplasm. The size of the pool was increased by decreasing the dimerization rate without affecting protein synthesis. This was achieved by decreasing Zn(++) in the growth medium. It was found that the cells contained a full complement of monomers, although the level of active enzyme was low. A process subsequent to the release of the monomers from the ribosomes was found to be limiting the formation of the finished enzyme. This process affects the level of the pool of monomers independently from their synthesis.
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PMID:Alkaline phosphatase subunits and their dimerization in vivo. 487 56

Four proteins, which have been designated A, B, C and D, have been purified from human parotid saliva. These proteins are the major constituents of parotid saliva which migrate rapidly to the anode in polyacrylamide electrophoresis at pH9.5. Gel filtration and polyacrylamide electrophoresis were employed in the purification procedures. After purification all four preparations were tested for homogeneity by electrophoresis at pH2.8 and 9.5, by isoelectric focusing in the pH range 3-10, by immunodiffusion, and by sedimentation in the analytical ultracentrifuge. None of the proteins showed significant activity in assays for amylase, acid and alkaline phosphatase, protease, lysozyme, ribonuclease, peroxidase, beta-glucuronidase, beta-galactosidase, iron-binding activity and esterase. No cross-reactions were detected with antisera specific for lactoferrin and 15 serum proteins. All four proteins were rich in glutamic acid, proline and glycine and were lacking completely the sulphur-containing amino acids. Proteins A and C contained no threonine or tyrosine. Carbohydrate could be demonstrated only in protein A at a concentration of 4% of the total protein.
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PMID:Purification and partial characterization of four proteins from human parotid saliva. 500 93

Group H streptococci (strain Challis) which are competent for transformation release a bacteriocin into liquid medium which is bacteriocidal for another group H streptococcus (strain Wicky). The streptocin (STH(1)) is resistant to treatment with deoxyribonuclease and ribonuclease but is sensitive to trypsin, phospholipase C, and alkaline phosphatase. Such enzyme sensitivity experiments indicate that the bacteriocin may be a complex molecule (protein and lipid) containing phosphate groups essential for activity. STH(1), which is readily distinguishable from competence factor and bacteriophage activity, appears to have no role in the initiation of the competent state in strain Wicky. The presence of this factor in Challis culture supernatant fluids indicates that a reevaluation of earlier studies performed with the Challis-Wicky transformation system may be necessary.
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PMID:Bacteriocin production by transformable group H streptococci. 508 61

A pancreatic ribonuclease digest of (14)C-labeled tobacco necrosis virus RNA was fractionated according to charge by column chromatography. Individual fractions were dephosphorylated with alkaline phosphatase and rechromatographed. The fraction, originally containing oligonucleotides with seven negative charges, separated into two components corresponding to five (-5) and two negative charges (-2). The -5 fraction was derived from the internal oligonucleotides while the -2 fraction must have originated from a 5'-pyrophosphorylated terminal trinucleotide. The sequence of this terminal trinucleotide was determined by column chromatography on DEAE-cellulose in a triethyl ammonium carbonate gradient, using the appropriate markers. The radioactivity chromatographed with a (ApGp)U marker. The order of the Ap and Gp was determined after ribonuclease T(1) and alkaline phosphatase digestion. The radioactivity in the product chromatographed with an ApG marker. The 5'-terminus of tobacco necrosis virus RNA was therefore determined as ppApGpUp..., which is identical to the terminus of the RNA of its satellite virus as previously determined (J. Mol. Biol., 38, 59 (1968); Science, 160, 1452 (1968)). The 5' pyrophosphate in both viruses was probably formed by an in vivo enzymatic removal of a gamma-phosphate from a triphosphate, and its presence in both viruses suggested a common site of synthesis. The identity of the 5'-terminal sequences is considered not to be fortuitous and is discussed from the standpoint of their role as a recognition site for the virus-specific RNA replicase.
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PMID:Identity of the 5'-terminal RNA nucleotide sequence of the satellite tobacco necrosis virus and its helper virus: possible role of the 5'-terminus in the recognition by virus-specific RNA replicase. 527 92

1. Two ribonucleases (aorta ribonuclease I and aorta ribonuclease II) from bovine aorta were purified 4611-fold and 667-fold respectively. Ethanolic precipitation, acid extraction, isoionic precipitation at pH3.5 and Bio-Rex 70 column chromatography were the methods employed. 2. Aorta ribonuclease I exhibited no deoxyribonuclease or alkaline phosphatase activity. 3. Aorta ribonuclease I appeared to be homogeneous when subjected to discontinuous gel electrophoresis. 4. Aorta ribonuclease II exhibited the same properties as aorta ribonuclease previously isolated. 5. The activities of the aorta ribonucleases and pancreatic ribonuclease on homopolymers and dinucleoside phosphates were compared. 6. Aorta ribonuclease I exhibited optimum pH7.5 and, under the assay conditions used, optimum temperature 60 degrees .
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PMID:Purification and characterization of bovine aorta ribonucleases. 534 73

Treatment of Spirillum itersonii with tris(hydroxymethyl)aminomethane (Tris)-ethylenediaminetetraacetate (EDTA) results in the quantitative release of alkaline phosphatase and ribonuclease into the surrounding medium. At the same time, about 90% of the total cellular soluble cytochrome c is liberated. This process occurs within 1 min of treatment at both 24 and 4 C. Release of these proteins by Tris-EDTA treatment is highly selective, since only 9% of the total cell protein is liberated, concomitantly with less than 5% ribonucleic acid, deoxyribonucleic acid, and malate dehydrogenase. Different sigmoidal curves are obtained for release of proteins as a function of EDTA concentration. The order of liberation with increasing EDTA is as follows: alkaline phosphatase, protein, soluble cytochrome c, and ribonuclease. Treatment of cells with Tris-EDTA under conditions which cause extensive loss of alkaline phosphatase, soluble cytochrome c, and ribonuclease results in cell death, with cessation of protein and ribonucleic acid synthesis. Cells treated with EDTA in phosphate buffer (in the absence of Tris) liberate a large portion of their soluble cytochrome c, but negligible amounts of alkaline phosphatase and ribonuclease. Addition of Tris to cells pretreated with phosphate-buffered EDTA releases high levels of alkaline phosphatase, but not ribonuclease. These results suggest that a common surface alteration is not solely responsible for release of periplasmic proteins. More likely, each protein of the periplasm is bound in an independent and specific manner.
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PMID:Selective release of proteins from Spirillum itersonii by tris (hydroxymethyl) aminomethane and ethylenediaminetetraacetate. 554 Oct 31

Pyrophosphate, p-nitrophenyl phosphate and a variety of pyrimidine and purine nucleotides are hydrolyzed by the solubilized membrane-bound enzymes of the brush border plasma membrane of Hymenolepis diminuta. The pH optima (or ranges) for hydrolysis of substrates are 8.0 (pyrophosphate), 8.8 (p-nitrophenyl phosphate), 8.4-8.9 (nucleoside monophosphates), and 7.1-8.1 (nucleoside triphosphates); all substrates, with the exception of nucleoside triphosphates, have a higher affinity for the solubilized enzyme at pH 7.4 than at their optimal pH for hydrolysis. ATP is degraded completely by the enzyme preparation to adenosine and inorganic phosphate, but since neither ADP nor ATP accumulate in the incubation medium it is not known whether ATP hydrolysis involves the sequential hydrolysis of terminal phosphate groups. Isoelectric focusing and various chromatographic procedures (gel permeation, ion-exchange and hydrophobic interaction chromatography) fail to separate the alkaline phosphatase, phosphodiesterase, 5'-nucleotidase, adenosine triphosphatase and ribonuclease activities associated with the solubilized membrane preparation. Additionally, inhibitor studies indicate that only a single enzyme with low substrate specificity is involved in the hydrolysis of nucleotides, p-nitrophenyl phosphate, pyrophosphate and hexose phosphate esters. Purines and pyrimidines and their nucleosides interact with the active site, and in some instances activity of the enzyme is stimulated by an unknown mechanism.
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PMID:Nucleotide hydrolysis by solubilized membrane-bound enzymes of the brush border plasma membrane of Hymenolepis diminuta. 613 88

The nascent DNA synthesized by permeable cells of Bacillus subtilis in the presence of 5'-mercurideoxycytidine triphosphate and 2',3'-dideoxyATP has been isolated and characterized. The newly synthesized DNA was isolated free from other cellular nucleic acids by affinity chromatography on thiol-substituted agarose. The number average chain length of the nascent DNA synthesized in one minute at 25 degrees C was 33 nucleotide residues, due to the chain-terminating action of 2',3'-dideoxyATP. Several lines of evidence indicated that at least 90% of the DNA thus isolated carried a terminally phosphorylated RNA moiety at its 5'-end: (1) the nascent DNA was resistant to exonucleolytic degradation by spleen phosphodiesterase unless first hydrolyzed by strong alkali or ribonuclease; (2) the 5'-termini of nascent DNA could not be phosphorylated by polynucleotide kinase unless first treated with alkaline phosphatase or subjected to hydrolysis by strong alkali or ribonuclease; (3) alkaline hydrolysis of nascent DNA labeled with 32P at the 5'-end released unlabeled DNA with a free 5'-terminus and 32P-labeled ribonucleoside 3',5'-bisphosphates; (4) ribonuclease degradation of similarly labeled material produced an unlabeled DNA-containing polynucleotide fraction and 32P-labeled ribo-oligonucleotides; (5) chromatography on dihydroxyboryl cellulose showed that the RNA moiety lacked a 3'-terminal cis-diol grouping (even after treatment with alkaline phosphatase) unless first subjected to the 3'-exonucleolytic action of bacteriophage T4 DNA polymerase. The sequence of the ribonucleotide chains was elucidated by end-group labeling with polynucleotide kinase and digestion with various ribonucleases. The ribonucleotide moiety was primarily three and four residues in length with the predominant sequence (pp)pApG(pC)1-2pDNA. The possibility that it represents a primer for discontinuous DNA synthesis is discussed.
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PMID:Analysis of the 5'-termini of nascent DNA chains synthesized in permeable cells of Bacillus subtilis. 618 36

Porcine rotaviral infectivity for continuous porcine kidney (PK-15) cells was enhanced by incorporation of pancreatic endopeptidases into the cell culture maintenance medium. Marked enhancement of infectivity was induced by trypsin, whereas elestase and alpha-chymotrypsin enhanced infectivity to a lesser extent. Bacterial protease also induced some enhancement of porcine rotaviral infectivity. A synergistic enhancement of porcine rotaviral infectivity was noticed with trypsin and alpha-chymotrypsin combined. Porcine rotaviral infectivity was not affected by incorporation of alpha-amylase, alkaline phosphatase, beta-galactosidase, carboxypeptidase-A, deoxyribonuclease, enterokinase, lipase, or ribonuclease into the maintenance medium.
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PMID:Porcine rotaviral infection of cell culture: effects of certain enzymes. 624 64


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