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:3.1.25.1 (deoxyribonuclease)
1,471 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Nuclei and chromatin isolated in the presence of calcium or magnesium from Rana catesbeiana liver tissue exhibit considerable endogenous deoxyribonuclease activity. This activity is present in liver nuclei isolated from froglets as well as in liver nuclei isolated from untreated and thyroid hormone treated premetamorphic tadpoles. Nuclei and chromatin isolated in the absence of divalent cations and in the presence of spermine exhibit no detectable expression of the endogenous deoxyribonuclease activity. The endogenous deoxyribonuclease present, but not expressed, in spermine-isolated tadpole liver nuclei or chromatin is salt extractable. Once dialyzed, the salt-extracted deoxyribonuclease is activated by calcium or magnesium. This deoxyribonuclease shows maximal enzyme activity in 15 mM calcium at pH 8.0 or in 15 mM magnesium at pH 7.4. After Ca2+ activation, deoxyribonuclease activity is maximally inhibited by amounts of spermine similar to that required to completely inhibit DNase I. Destruction of the salt-extracted deoxyribonuclease activity by treatment with proteinase K or heat suggests that it is of a proteinaceous nature. The localization and nature of this enzyme activity established that it is associated with the salt-soluble proteins affiliated with tadpole and froglet liver chromatin.
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PMID:Chromatin-associated deoxyribonuclease activity in liver nuclei isolated from Rana catesbeiana froglets and premetamorphic and T3-induced tadpoles. 697 71

An investigation was performed with the use of physical techniques, to determine the nature and organization of inverted repeat sequences in nuclear DNA fragments from Physarum polycephalum. From the average size of foldback duplexes (550 nucleotide pairs), and the foldback duplex yield as determined by treatment of DNA with S1 deoxyribonuclease followed by hydroxyapatite chromatography, it is estimated that there are at least 25000 foldback sequences in the Physarum genome. Foldback DNA molecules exhibit properties intermediate between single-stranded DNA and native duplexes on elution from hydroxyapatite with a salt gradient. In addition, thermal-elution chromatography of foldback DNA from hydroxyapatite crystals shows that foldback duplexes are less stable than native DNA. These properties can be explained on the basis that inverted repeat sequences are mismatched when in the foldback configuration. The results of experiments in which the binding of foldback DNA molecules to hydroxyapatite was determined, by using fragments of different single-chain size, agree with previous studies indicating that inverted repeat sequences are located, on average, every 7000 residues throughout the Physarum genome. The inverted repeats are derived from both the repetitive and single-copy components in Physarum nuclear DNA.
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PMID:Sequence organization in nuclear deoxyribonucleic acid from Physarum polycephalum. Physical properties of foldback sequences. 740 56

Two proteins, which may be involved in DNA replication, have been isolated and characterized from the eukaryote Tetrahymena thermophila. One of these proteins, DNA polymerase, has been purified to apparent homogeneity. The enzyme has a native molecular weight of approximately 90 000 in the presence of salt and aggregates to higher-molecular-weight forms in the absence of salt. Purified preparations of the enzyme yield a major subunit of Mr 45 000 when the protein is analyzed by denaturing electrophoresis. Tetrahymena DNA polymerase requires a divalent cation for catalysis and prefers gapped template-primers over denatured and native DNAs. A template-primer such as poly(dT) . oligo(A) can also be elongated by the DNA polymerase. However, the enzyme will not use poly(A) . oligo(dT) as a template-primer. Sulfhydryl-blocking reagents, such as N-ethylmaleimide, inhibit Tetrahymena DNA polymerase. The DNA polymerase lacks assayable levels of both single and double-stranded deoxyribonuclease activity. Throughout the early stages of purification the DNA polymerase chromatographs together with a protein of molecular weight 100 000. This protein, which yields a single major polypeptide of Mr 25 000 when analyzed by denaturing electrophoresis, has single-stranded-DNA-binding properties and has the ability to stimulate both the rate and extent of DNA-polymerase-catalyzed DNA synthesis in vitro. By virtue of this latter ability, the protein has been referred to as the M (for 'modifying') protein. Maximum stimulation of DNA polymerase was achieved with template-primers, which contained large stretches of single-stranded template such as poly(dA) . (dT)10 mixed in a template-to-primer ratio of one to one. Stimulation of DNA polymerase activity by M protein in vitro appears to involve formation of longer product DNA.
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PMID:Purification from Tetrahymena thermophila of DNA polymerase and a protein which modifies its activity. 746 Sep 43

In this paper we present a sensitive procedure to determine specifically the induction as well as the removal of cyclobutane pyrimidine dimers in intact mammalian cells without radioactive labeling of the DNA. This technique allows the detection of DNA damage by UV doses as low as 0.1 J/m2. The method consists of gentle lysis of cell monolayers, high-salt treatment and incubation with the cyclobutane pyrimidine dimer-specific repair enzyme T4 endonuclease V, followed by alkaline unwinding, hydroxyapatite chromatography and fluorimetric DNA analysis. The number of T4 endonuclease V-sensitive sites correlates well with the amount of UV-induced cyclobutane pyrimidine dimers reported in the literature, indicating that these cyclobutane pyrimidine dimers are recognized quantitatively by the system. The assay is easily transferable to the detection of other types of DNA adducts by applying different damage-specific repair enzymes, providing a sensitive method to investigate the induction and the repair of DNA lesions without the use of radioactive labeling.
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PMID:Sensitive nonradioactive detection of UV-induced cyclobutane pyrimidine dimers in intact mammalian cells. 753 91

We describe a deoxyribonuclease activity from nuclear protein extracts of cultured Aedes albopictus mosquito cells. The nuclease cleaved linear and circular double-stranded DNA, first generating 3' OH single-stranded nicks followed by second strand cleavage, but had little or no exonucleolytic activity. Detection of this activity was optimal at pH 7.1, in the presence of a divalent cation (Mg2+, Ca2+, Mn2+, Ba2+). In the presence of Mg2+, Zn2+, Hg2+ and Cu2+ inhibited activity, sulfhydryl reagents and ATP had no effect. At physiological temperatures (18-35 degrees C), linear double-stranded DNA probes were preferentially cleaved near sites containing 3-6 consecutive deoxyadenine/thymine base pairs. Results from salt dependency and drug inhibition studies, combined with inspection of DNA sequence, suggested that DNA structure is among the parameters that determine preferred cleavage sites.
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PMID:Evidence for DNA endonuclease activity in nuclear extracts from mosquito cells. 785 41

The survival of Staphylococcus aureus was studied in 30 oral administration liquid medicaments (15 syrups and 15 solutions) to determine the effectiveness of the preservatives, the influence of the culture medium used in the enumeration of the surviving microorganisms, and the loss of the enzyme coagulase, phosphatase, DNase (deoxyribonuclease), and thermonuclease. Samples were inoculated with 6.3-6.5 x 10(5) viable cells per milliliter and were stored at room temperature for 60 days. Aliquots were taken for analysis at 0, 15, 22, 30, and 60 days after samples were inoculated. The enumeration of S. aureus was made by most probable number method (MPN) with six liquid culture media: triptone soy (TS), TS with 10% NaCl (TSS), TS and TSS with 0.2% catalase, Mannitol salt, and Tellurite-mannitol-glycine. The survival of S. aureus was lower in solutions than in syrups, decreased with the storage time, and depended on the culture medium utilized in the enumeration. Nonselective media were more sensitive than selective ones; that is, a better percentage of recovery was achieved with TS and the catalase medium. The preservative was effective in 93.3% of the samples. Coagulase was the most stable enzyme and phosphatase, DNase, and thermonuclease disappeared during the storage period.
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PMID:Survival of Staphylococcus aureus in oral administration liquid medicaments and influence of count medium on survival. 844 30

The UL12 open reading frame of herpes simplex virus type 1 (HSV-1) encodes a deoxyribonuclease that is frequently referred to as alkaline nuclease (AN) because of its high pH optimum. Recently, an alternate open reading frame designated UL12.5 was identified within the UL12 gene. UL12.5 and UL12 have the same translational stop codon, but the former utilizes an internal methionine codon of the latter gene to initiate translation of a 60-kDa amino-terminal truncated form of AN. Since the role of the UL12.5 protein in the HSV-1 life cycle has not yet been determined, its properties were investigated in this study. Unlike AN, which can be readily solubilized from infected cell lysates, the UL12.5 protein was found to be a highly insoluble species, even when isolated by high-salt detergent lysis. Since many of the structural polypeptides which constitute the HSV-1 virion are similarly insoluble, a potential association of UL12.5 protein with virus particles was examined. By using Western blot analysis, the UL12.5 protein could be readily detected in preparations of intact virions, isolated capsid classes, and even capsids that had been extracted with 2 M guanidine-HCl. In contrast, AN was either missing or present at only low levels in each of these structures. Since the inherent insolubility of the UL12.5 protein prevented its potential deoxyribonuclease activity from being assayed in infected-cell lysates, partially purified fractions of soluble UL12.5 protein were generated by selectively solubilizing either insoluble infected-cell proteins or isolated capsid proteins with urea and renaturing them by stepwise dialysis. Initial analysis of these preparations revealed that they did contain an enzymatic activity that was not present in comparable fractions from cells infected with a UL12.5 null mutant of HSV-1. Additional biochemical characterization revealed that UL12.5 protein was similar to AN with respect to pH optimum, ionic strength, and divalent cation requirements and possessed both exonucleolytic and endonucleolytic functions. The finding that the UL12.5 protein represents a capsid-associated form of AN which exhibits nucleolytic activity suggests that it may play some role in the processing of genomic DNA during encapsidation.
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PMID:The product of the UL12.5 gene of herpes simplex virus type 1 is a capsid-associated nuclease. 906 Jun 64

A neutral Mg(2+)-dependent deoxyribonuclease from the Colorado potato beetle was isolated and characterized in physicochemical terms. An electrophoretically homogeneous preparation of the enzyme was obtained using salt fractionation, Sephadex G-100 gel filtration, and subsequent preparative isoelectrofocusing in an Ultrodex layer. The molecular weight of the purified DNase preparation (with a purification degree of 104) and its isoelectric point were 100 kD and 9.1, respectively. The enzyme activity was maximal at pH 7.2 and 46 degrees C in the presence of 10 mM Mg2+. The DNase of the Colorado beetle preferentially hydrolysed denatured DNA via the endonuclease pathway, degrading the substrate to oligonucleoside-3'-phosphates. As far as the physical and chemical properties are concerned, this Colorado beetle DNase seems different from previously investigated DNases of other insect species.
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PMID:Isolation, purification, and characterization of a neutral Mg(2+)-dependent deoxyribonuclease of the Colorado potato beetle Leptinotarsa decemlineata Say. 936 Mar 4

Endonuclease V from bacteriophage T4, is a cis-syn pyrimidine dimer-specific glycosylase. Recently, the first sequence homolog of T4 endonuclease V was identified from chlorella virus Paramecium bursaria chlorella virus-1 (PBCV-1). Here we present the biochemical characterization of the chlorella virus pyrimidine dimer glycosylase, cv-PDG. Interestingly, cv-PDG is specific not only for the cis-syn cyclobutane pyrimidine dimer, but also for the trans-syn-II isomer. This is the first trans-syn-II-specific glycosylase identified to date. Kinetic analysis demonstrates that DNAs containing both types of pyrimidine dimers are cleaved by the enzyme with similar catalytic efficiencies. Cleavage analysis and covalent trapping experiments demonstrate that the enzyme mechanism is consistent with the model proposed for glycosylase/AP lyase enzymes in which the glycosylase action is mediated via an imino intermediate between the C1' of the sugar and an amino group in the enzyme, followed by a beta-elimination reaction resulting in cleavage of the phosphodiester bond. cv-PDG exhibits processive cleavage kinetics which are diminished at salt concentrations greater than those determined for T4 endonuclease V, indicating a possibly stronger electrostatic attraction between enzyme and DNA. The identification of this new enzyme with broader pyrimidine dimer specificity raises the intriguing possibility that there may be other T4 endonuclease V-like enzymes with specificity toward other DNA photoproducts.
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PMID:Characterization of a novel cis-syn and trans-syn-II pyrimidine dimer glycosylase/AP lyase from a eukaryotic algal virus, Paramecium bursaria chlorella virus-1. 958 53

Firshein, William (Wesleyan University, Middletown, Conn.). Effect of manganese and enzymatic deoxyribonucleic acid digests on population changes and respiration of pneumococci. J. Bacteriol. 84:478-484. 1962.-Deoxyribonucleic acid (DNA; Na salt) treated with deoxyribonuclease and Mn(++) (as MnSO(4)) stimulated R (avirulent) to S (virulent) population changes in vitro. Under certain environmental conditions and with certain strains, Mn(++) alone elicited these changes, but, in most cases, both digested DNA and Mn(++) were necessary for maximal effect. These population changes were due to a selective stimulation of the multiplication of S cells and a delay in S-cell lysis, with either a slight inhibitory effect or no effect against the multiplication of R cells. The magnitude of the population change depended upon the presence of digested DNA, the level of Mn(++), the strain, and the concentration of basal medium. Mn(++) enhanced respiration of S cells while inhibiting that of R cells.
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PMID:Effect of manganese and enzymatic deoxyribonucleic acid digests on population changes and respiration of Pneumococci. 1394 41


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