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:2.7.7.7 (DNA polymerase)
17,007 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A highly active and stable DNA polymerase was found in purified preparations of two murine sarcoma viruses. Enzyme activity is not detected in most virus preparations unless they are treated with low concentrations of a nonionic detergent such as Nonidet P-40. The incorporation of labeled thymidine triphosphate requires all four deoxyribonucleoside triphosphates and either Mg(2+) or Mn(2+). Enzyme activity is proportional to virus concentration and is linear with time up to 90 min. That the template is RNA is suggested by the reduction in polymerase activity upon treatment of murine sarcoma virus with RNase, and by the absence of detectable amounts of DNA in the virus. That the product is DNA is shown by the incorporation of all four deoxyribo-nucleoside triphosphates into an acid-insoluble product which is stable in alkali, is destroyed by DNase, sediments in alkaline sucrose gradients with a sedimentation coefficient of 7 S, and bands in isopycnic CsCl gradients with a mean buoyant density of 1.700.
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PMID:Mechanism of carcinogenesis by RNA tumor viruses. I. An RNA-dependent DNA polymerase in murine sarcoma viruses. 431 86

We have determined the levels of DNA polymerase, DNA ligase, a DNase acting on single-stranded DNA, an endonuclease making single-strand breaks in double - stranded DNA and polynucleotide kinase in fibroblasts obtained from nine normal persons and from nine patients with Xeroderma Pigmentosum; the pathological lines belong to the different described clinical forms and to the three different complementation groups described so far. All the enzymes are present in the normal lines and in the Xeroderma lines. The levels are quite variable, but the values obtained in the pathological lines lie within the ones observed in the normal population.
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PMID:Levels of some enzymes acting on DNA in xeroderma pigmentosum. 441 76

The stimulation of human lymphocytes with phytohaemoagglutinin induces the appearance or increase of several enzymes of DNA metabolism [Pedrini etal., Biochem. Biophys. Res. Comm., 47:1221(1972)]. With long times of stimulation, two phenomena are observed; an increase in the levels of DNA polymerase, of a DNase acting on single-stranded DNA, and of an endonuclease, occurring between the third and fourth day, in parallel with a wave of DNA synthesis;a second wave of increase of the same enzymes and of DNA ligase,occurring between the fifth and eight day when the DNA replication rate, as measured by thymidine-pulses, has decreased to values close to the background.
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PMID:Evidence for two waves of induction of DNA enzymes in stimulated human lymphocytes. 445 22

R-DNA polymerase, D-DNA polymerase, DNase and RNase H activities in mitochondria from chick embryonic brain were studied by ion-exchange chromatography. Two main fractions were separated according to their chromatographic behaviour: a fraction M Ib which is eluted with the washing buffer from two successive DEAE-cellulose columns and a fraction M IV which is eluted at 400 mM KC1 from a phosphocellulose column. Although the two fractions contain both the DNA polymerase and the degrading activities, all the specific activities are higher in fraction M IV than in fraction M Ib. Heat inactivation experiments have shown that R-DNA polymerase is inactivated in both fractions, whereas RNase H and DNase are not affected. Thus, degrading activities and R-DNA polymerase activity seem to be catalyzed by different molecular entities. However the fact that in most cases these activities co-chromatograph suggests that the corresponding molecules form rather stable complexes.
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PMID:Mitochondrial DNA polymerase, deoxyribonuclease and ribonuclease H activities from brain of chick embryo. 447 11

The effect of histones on accessibility of DNA to DNase in chromatin of thymus nuclei has been studied by selective extraction of either lysine-rich or arginine-rich histones. It was found that all histones block accessibility but that, weight for weight, lysine-rich histones block much more effectively than do arginine-rich histones. We point to the contrast between accessibility of DNA to DNase and of DNA to RNA polymerase, and to what may be the similarity between accessibility to DNase and DNA polymerase.
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PMID:Blocking by histones of accessibility to DNA in chromatin. 450 81

DNA polymerase activity was detected in each of eight preparations of concentrated human hepatitis B antigen (HBAg) rich in Dane particles prepared by high-speed centrifugation of antigen-positive human plasma and in none of seven control preparations prepared in the same way from HBAg-negative plasma. The incorporation of (3)H-thymidine-methyl-5'-triphosphate into DNA was dependent on four deoxyribonucleoside triphosphates and MgCl(2). Treatment of the concentrated HBAg preparations with the nonionic detergent Nonidet P-40 (NP40) more than doubled the enzyme activity. Fractionation of the concentrated HBAg preparation in sucrose density gradients after treatment with NP40 revealed that the enzyme activity appeared within the density range of Dane core antigen but at a slightly higher density than the average for core antigen. The only particles observed by electron microscopy in this region of the gradient were typical 28-nm cores, suggesting that the DNA polymerase activity was associated with a subpopulation of cores. No DNA polymerase activity was found in purified 20-nm HBAg particles. The DNA product of the reaction remained associated with the 110S core and was not susceptible to DNase digestion when associated with the core. Inhibition of the reaction by actinomycin D and daunomycin suggested that the reaction was dependent on a DNA template associated with the core.
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PMID:DNA polymerase associated with human hepatitis B antigen. 476

Particles containing DNA polymerase (Dane particles) were purified from the plasma of chronic carriers of hepatitis B antigen. After a DNA polymerase reaction with purified Dane particle preparations treated with Nonidet P-40 detergent, Dane particle core structures containing radioactive DNA product were isolated by sedimentation in a sucrose density gradient. The radioactive DNA was extracted with sodium dodecyl sulfate and isolated by band sedimentation in a preformed CsCl gradient. Examination of the radioactive DNA band by electron microscopy revealed exclusively circular double-stranded DNA molecules approximately 0.78 mum in length. Identical circular molecules were observed when DNA was isolated by a similar procedure from particles that had not undergone a DNA polymerase reaction. The molecules were completely degraded by DNase 1. When Dane particle core structures were treated with DNase 1 before DNA extraction, only 0.78-mum circular DNA molecules were detected. Without DNase treatment of core structures, linear molecules with lengths between 0.5 and 12 mum, in addition to the 0.78-mum circles were found. These results suggest that the 0.78-mum circular molecules were in a protected position within Dane particle cores and the linear molecules were not within core structures. Length measurements on 225 circular molecules revealed a mean length of 0.78 +/- 0.09 mum which would correspond to a molecular weight of around 1.6 x 10(6). The circular molecules probably serve as primer-template for the DNA polymerase reaction carried out by Dane particle cores. Thermal denaturation and buoyant density measurements on the Dane particle DNA polymerase reaction product revealed a guanosine plus cytosine content of 48 to 49%.
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PMID:DNA of a human hepatitis B virus candidate. 484 28

The presence is reported of an RNA-instructed DNA polymerase in visna virus, the causative agent of a "slow" neurological disease in sheep. The product synthesized by the RNA-directed reaction has been shown to be a DNA heteropolymer by the following criteria: synthesis requires the presence of all four deoxyriboside triphosphates; the product is resistant to ribonuclease and alkali but is degraded by DNase; and the product has a density of 1.420 in Cs(2)SO(4) solution, characteristic of DNA.Visna virions, like those of the oncogenic RNA viruses, contain DNA polymerase activities that respond to a variety of double-stranded DNAs and to synthetic DNA.RNA hybrids.
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PMID:DNA polymerase activities in varions of visna virus, a causative agent of a "slow" neurological disease. 499 14

We examined the effect of 9-(1,3-dihydroxy-2-propoxymethyl)guanine (DHPG) on viral DNA, RNA, protein, and enzyme synthesis in HeLa cells infected with herpes simplex virus type 1 and type 2. DHPG inhibited virus DNA synthesis in a dose-dependent fashion. This inhibition was not due to the lack of deoxynucleoside triphosphates which are required for DNA synthesis. This compound has no apparent effect on early and late viral RNA synthesis, viral protein synthesis, or viral thymidine kinase, DNA polymerase, and DNase induction in virus-infected cells.
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PMID:Effects of 9-(1,3-dihydroxy-2-propoxymethyl)guanine, a new antiherpesvirus compound, on synthesis of macromolecules in herpes simplex virus-infected cells. 609 51

The delay in the replication of herpes simplex virus surviving u.v. irradiation occurs after the uncoating of virus, as judged by sensitivity to DNase. It occurs before translation, judged by the kinetics of appearance of various virus-specific proteins, and before transcription, judged by the detection of virus-specific RNA by in situ hybridization. Since the delays in both transcription and translation are reversed by photoreactivation, the simplest hypothesis is that pyrimidine dimers directly obstruct transcription;unless these are broken by photoreactivating enzymes, there will be transcriptional delay until reactivating processes have repaired the lesion. The u.v. sensitivities of the abilities to induce various enzymes (thymidine kinase, DNase and DNA polymerase) were only about four times less than that of infectivity. The The ability to induce the three enzymes was three times less sensitive than that of the structural antigen (Band II).
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PMID:Ultraviolet irradiation of herpes simplex virus (type 1): delayed transcription and comparative sensitivites of virus functions. 625 90


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