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)

Four distinct DNA-dependent DNA polymerase activities (DNA polymerases I, II, III and IV according to the order of elution from a DEAE column) have been separated from extracts of unfertilized Xenopus laevis eggs. The same activities, on the basis of their chromatographic properties, template specificities and sedimentation coefficients, have been found in embryos at least until the gastrula stage. On the other hand, Xenopus kidney cells grown in culture, as well as full grown oocytes lack DNA polymerase I. These data suggest the DNA polymerase I might be a special DNA polymerase activity involved in the extremely rapid DNA synthesis which takes place during early development of X. laevis.
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PMID:Multiple forms of DNA-dependent DNA polymerase during early development and in somatic cells of Xenopus laevis. 0

9-O-methyloximd erythromycin A and its analogue inhibited reverse transcriptase and blocked focus formation of Rous sarcoma virus. These chemicals inhibited neither DNA-dependent DNA polymerase nor DNA-dependent RNA polymerase from bacterial sources. However, they inhibited reverse transcriptase with an apparently differnt mechanism than that by rifamycin ABDP.
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PMID:Oxime derivatives of erythromycin: inhibitors of Rous sarcoma virus reverse transcriptase activity and focus formation. 4 82

A method for the determination of the Bleomycin-inactivating enzyme is described. The amount of conversion of active Bleomycin to inactive Bleomycin is used as a measure for the determination of the Bleomycin-inactivating enzyme activity. The active Bleomycin is determined in a DNA-dependent DNA polymerase assay; in a certain Bleomycin concentration range the resulting reduction of the activity of the DNA-dependent DNA polymerase is correlated linearly when plotted semilogarithmically. By application of this method it has been found that the activity of the Bleomycin-inactivating enzyme is highest in liver and present in lower concentrations in testis, spleen, lung, brain, and skin.
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PMID:Determination of the bleomycin-inactivating enzyme in biopsies. 6 6

Bleomycin (BLM) exclusively affects thymidine-containing compounds such as DNA and polydeoxyribonucleotides by releasing free thymine and leaving aldehyde functions. Molecular morphology and base sequence of the DNA strongly influence BLM activity. High BLM concentrations, besides modifying DNA into oligothyminic or athyminic nucleic acids, cause strand scissions. Enzymatic DNA and RNA synthesis is strongly influenced by BLM. The inhibition in DNA-dependent DNA polymerase and DNA-dependent RNA polymerase assays is of the non-competitive type. Protein biosynthesis in in vitro systems is not affected by BLM even at high concentrations. BLM turns out to be a strong inhibitor of DNase I and of DNase II; the inhibition is of the competitive type. The enzymatic activities of nucleases using RNA as substrate (RNase A, RNase B, Rnase T1, venom phosphodiesterase I and spleen phosphodiesterase II) are not influenced by this antibiotic. The antibiotic reduces cell proliferation (L5178y mouse lymphoma cells) in vitro in low concentrations by cytostasis and at higher concentrations by cytotoxicity. In BLM-treated L5178y cells, DNA synthesis is strongly reduced, while RNA and protein synthesis are not affected. In vivo, using growing quail oviducts, cell proliferation and cytodifferentiation are markedly inhibited after BLM treatment. This is attributed to the observed inhibition of DNA synthesis. RNA and protein synthesis as well as gene expression are not influenced by BLM under the conditions used. The selective inhibition of DNA synthesis in vivo may be caused by the following mechanisms: (1) competition of BLM with RNA; (2) blocking of the accessibility of DNA in chromatin to BLM, and (3) dependence from the repair processes. BLM inhibits growth of sarcomas, induced by oncogenic RNA viruses in vivo; well-developed tumours show regression after BLM treatment. Transformation of chick embryo fibroblasts by oncogenic RNA viruses in vitro and growth of these viruses is blocked by BLM; the most sensitive period for BLM inhibition is the time during the first period (integration of viral genome into cellular genome?) after infection.
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PMID:Effect of bleomycin on DNA, RNA, protein, chromatin and on cell transformation by oncogenic RNA viruses. 6 69

The activities of streptovaricin complexes, streptovaricins, streptovals, and streptovarinic degradation products were elevated against RNA-directed DNA polymerases of Rauscher leukemia virus, DNA-dependent DNA polymerase of bacterial and mammalian cells, and DNA-dependent RNA polymerases of mammalian origin. The activities of streptovaricins were also listed for comparison purposes. The effects of streptovaricin complexes on viral DNA polymerases varied significantly from lot to lot, and streptovaricin complex lot 7 was the most active. All the streptovals and streptovaricin degradation products except varicinal A showed a marked improvement (twofold to tenfold) in activity against the viral enzyme over the parent streptovaricins. None of these compounds, however, displayed any significant effect on either the DNA polymerase of L1210 leukemia cells and Escherichia coli or the RNA polymerase of isolated nuclei of mouse liver. As a result of tests in these systems, some specific inhibitors of RNA-directed DNA polymerases of Rauscher leukemia virus were selected.
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PMID:Effects of streptovaricins and their degradation products on RNA-directed DNA polymerase of Rauscher leukemia virus. 6 15

beta-Lapachone is a naturally occuring compound that can be isolated from a number of tropical trees. It is shown to be a potent inhibitor of reverse transcriptase activity from both avian myeloblastosis virus and Rauscher murine leukaemia virus. In addition, it affects eukaryotic DNA-dependent DNA polymerase-alpha activity: 50% inhibition is reached in 60-min incubation time by about 8 micron beta-lapachone. Enzyme activity is inhibited irrespective of the purity of the enzyme used or of the amount or type of template/primer or substrate present. The inhibitory effect of the drug is only observed in the presence of dithiothreitol. The primary site of action of beta-lapachone appears to be the enzyme protein, as is also borne out by the specificity of its action. Eukaryotic DNA-dependent DNA polymerase-beta, prokaryotic DNA-dependent DNA polymerase I, several other nucleic acid polymerases and some completely unrelated enzymes are not affected. Reverse transcriptase and DNA-dependent DNA polymerase-alpha may be in someway related in possessing similarly exposed '--SH structures' in their active sites. beta-lapachone thus affords a novel means of studying such interrelationships and of further characterizing enzymes.
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PMID:beta-Lapachone, an inhibitor of oncornavirus reverse transcriptase and eukaryotic DNA polymerase-alpha. Inhibitory effect, thiol dependence and specificity. 7 23

The hepatitis B virus (HBV), the causal agent of serum hepatitis, has a diameter of 42 nm and is comprised of an outer surface coat and a 27 nm core. A unique DNA-dependent DNA polymerase is associated with the core of the virus. The core also houses a circular DNA that contains both double-stranded and single-stranded regions. In the endogenous reaction, the DNA polymerase repairs the single-stranded gaps of the viral DNA. The surface protein of the virus, called hepatitis B surface antigen, contains both lipid and carbohydrate, and is often present in particulate form in the blood of infected patients. In Asia and Africa HBV infection is associated with subsequent development of primary hepatocellular carcinoma. Although most patients recover completely from acute illness, the hepatitis B virus may cause chronic infection. Recently, a virus similar to human HBV was discovered in woodchucks. HBV has not yet been propagated in a cell culture system and the mode of replication of this unusual virus in hepatocytes is still moot. Although reliable therapy has not yet been provided, the problem of this world-wide infection has led to many interesting approaches to both vaccine production and anti-viral chemotherapy.
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PMID:The hepatitis B virus and its DNA polymerase: the prototype three-D virus. 9 Oct 92

Bacillus subtilis W23 was infected with a clear-plaque variant of SP-10 phage, namely, SP-10c. Exogenous thymidine was not incorporated into phage DNA (even in the presence of deoxyadenosine), nor was there any transfer of thymidine nucleotides from bacterial to viral DNA. The lytic program was unaffected by concentrations of 5-fluorodeoxyuridine sufficient to reduce bacterial DNA synthesis by greater than 95%. Although these data are consistent with the interpretation that thymidine nucleotides are excluded from phage DNA, formic acid digests of SP-10c DNA contained what appeared to be the four conventional bases; however, adenine and thymine were not recovered in equimolar yields. DNA-RNA hybridization and hybridization competition experiments were done. Synthesis of host RNA started to wane moments postinfection and stopped completely by 36 min. SP-10c coded for discrete classes of early and late RNA. The possibility of discrete subclasses of early RNA exists. Replication of the bacterial genome appeared to terminate 12 min postinfection. Degradation of the host DNA to acid-soluble material started at 36 min and, by the end of the latent period, greater than 90% of the host chromosome was hydrolyzed. Four apparent phage-coded enzymes have been identified. A di- and triphosphatase degraded dUTP, dUDP, dTTP, and dTDP (and, to a lesser extent, dCDP and d CTP) to the corresponding monophosphates; the enzyme had no apparent activity on dATP and dGTP. SP10c also coded for a DNA-dependent DNA polymerase, lysozyme, and a nuclease that degrades native bacterial DNA. Judging from the dependence of enzyme synthesis on the time of addition of rifampin (an inhibitor of the initiation of RNA synthesis), messengers for the di- and triphosphatase, as well as the nuclease, are transcribed from promoters that start to function 6 min postinfection. Promoters for polymerase and lysozyme did not become functional until 8 and 16 min postinfection, respectively.
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PMID:SP-10 bacteriophage-specific nucleic acid and enzyme synthesis in Bacillus subtilis W23. 13 89

Evidence was presented that in vitro conversion of single-stranded DNA of phage phi X 174 to the double-stranded replicative form by partially purified DNA-dependent DNA polymerase I requires a specific RNA fragment acting as primer (25-50 nucleotides). RNA fragments highly rich in nucleotides A and G were obtained by partial degradation of E. coli M 500 Sho-R ribosomal RNA with pancreatic ribonuclease. They become covalently bound to the newly synthesized DNA chain of the replicative form of phage phi X 174. These RNA fragments are also required for in vitro replication of lambda phage DNA.
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PMID:[RNA fragments rich in G and A nucleotides obligatory for in vitro DNA replication of phages phi-X 174 and lambda]. 17 51

9-beta-D-Arabinofuranosyladenine 5'-triphosphate (ara-ATP) is an inhibitor both of DNA polymerase-alpha and -beta from noninfected rabbit kidney cells and of the DNA-dependent DNA polymerase induced by herpes simplex virus Type 1 (strain IES). The studies were performed with partially purified enzymes, and each of the different polymerase preparations contained only one DNA-dependent DNA polymerase species. These enzymes were inhibited in a competitive manner. The HSV-induced DNA-dependent DNA polymerase was 39-fold more sensitive to ara-ATP than was cellular DNA polymerase-beta and 116-fold more sensitive than cellular DNA polymerase-alpha. The affinity of the HSV-induced enzyme for ara-ATP was only slightly influenced by the use of different template/initiators in the enzyme assays. In intact cell systems DNA synthesis was affected by 9-beta-D-arabinofuranosyladenine (ara-A) as indicated by the reduced incorporation of deoxythymidine. In herpesvirus-(strain Lennette)-infected cells, however, ara-A shows no influence on the incorporation on deoxythymidine into cellular DNA, but it substantially reduces the incorporation into viral DNA. Ara-A itself is incorporated into both cellular and herpesviral (strain Lennette, D-316 and IES) DNA during DNA synthesis.
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PMID:Inhibition of herpesvirus DNA synthesis by 9-beta-D-arabinofuranosyladenine in cellular and cell-free systems. 21 80


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