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)

In order to ascertain the identity of the DNA-dependent DNA polymerase responsible for the observed DNA synthesis in nuclei isolated from baby-hamster kidney (BHK-21/C13) cells a comparative study was carried out on the effects of some drugs, reported to influence DNA synthesis, on DNA synthesis catalysed by these nuclei and by partially purified DNA polymerase-alpha and -beta. In all cases DNA synthesis by isolated nuclei and polymerase-alpha was inhibited to similar extents by N-ethylmaleimide, p-hydroxymercuribenzoate, novobiocin, heparin and phosphonoacetic acid; polymerase-beta was much less affected by these compounds. Ethidium bromide inhibited all DNA synthesis to similar extents, although at low concentrations (about 2 microgram/ml) synthesis in isolated nuclei was stimulated. The results are discussed in relation to the proposal that DNA polymerase-alpha catalyses the covalent extension of Okazaki fragments that these nuclei carry out in vitro.
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PMID:Effect of drugs on deoxyribonucleic acid synthesis in isolated mammalian cell nuclei. Comparison with partially purified deoxyribonucleic acid polymerases. 45 71

At a concentration of 0.5 to 3 mmol/l, ATP stimulates the activity of mitochondrial DNA polymerase of Neurospora crassa under the optimum reaction conditions; at higher concentrations, an inhibitory effect is observed. 4-Chloromercuribenzoate (1 mmol/L), a thiol inhibitor, decreases the enzyme activity two-fold, while N-ethylmalcimide (2 mmol/L) has no effect. Ethidium bromide (up to 10 mumol/L) and heparin (up to 0.4 micrograms/mL) reduce the activity by 60%. ddTTP does not affect the DNA polymerase reaction. The best in vitro template is the activated calf-thymus DNA.
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PMID:Effect of activators and inhibitors on the activity of mitochondrial DNA polymerase. 184 56

Nitroakridin 3582 (NA) formed complexes with native deoxyribonucleic acid (DNA) and with transfer ribonucleic acid (tRNA) species from Escherichia coli. Spectrophotometric titrations of NA with these nucleic acids produced numerical results from which nonlinear adsorption isotherms were derived. These curves indicated the existence of more than one class of binding sites on the polymers to which NA was bound by more than one process. The stoichiometry of strong binding of NA to double helical DNA was in agreement with a conventional value (1 ligand molecule per 4.2 component nucleotides) for complete intercalation binding. NA inhibited the DNA-dependent DNA polymerase I and RNA polymerase reactions, the first strongly and the second appreciably. These inhibitions corresponded to the extents to which NA inhibits DNA and RNA biosyntheses in vivo. Evidently, NA interferes with the template function of DNA. The drug also inhibited the polymerization of phenylalanine in a cell-free E. coli ribosome-polyuridylic acid [poly (U)] system. The effect paralleled an inhibition of the poly (U)-directed binding of phenylalanyl tRNA to ribosomes. Ethidium bromide acted similarly. The antimalarial drug, chloroquine, stimulated polyphenylalanine synthesis, apparently as a result of stimulating the poly (U)-directed binding of phenylalanyl tRNA to ribosomes.
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PMID:Antibacterial nitroacridine, Nitroakridin 3582: binding to nucleic acids in vitro and effects on selected cell-free model systems of macromolecular biosynthesis. 494 80

Isolated chloroplasts are capable of synthesizing chloroplast DNA in the presence of Mg2+ and deoxynucleoside triphosphates. The in vitro reaction proceeds for at least 60 min and is inhibited by KC1 and N-ethylmaleimide. Stretches of several hundred nucleotides in length are synthesized within an hour. Little or no inhibition is shown by aphidicolin (an inhibitor of eukaryotic DNA polymerase alpha), dideoxythymidine triphosphate (an inhibitor of eukaryotic DNA polymerases beta and gamma), nalidixic acid, or rifampicin. Ethidium bromide is a moderate inhibitor of DNA synthesis in the isolated chloroplast. Soluble extracts of chloroplasts will copy exogenously added recombinant plasmid circular DNA containing fragments of chloroplast DNA, and this reaction is strongly inhibited by ethidium bromide. Copying of the plasmid DNA takes place on the relaxed circular or linear forms of the DNA, but no specific initiation sites on the chloroplasts' DNA fragments of the recombinant plasmids have been detected. Our data are consistent with a repair mechanism operating in vitro but may also represent incomplete replicative DNA synthesis.
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PMID:Deoxyribonucleic acid synthesis in isolated chloroplasts and chloroplast extracts of maize. 681 Sep 20

Intercalating agents, some of them in clinical use, were tested for their ability to inhibit the hepatitis B virus specific DNA polymerase reaction. Ethidium bromide was shown to be the strongest inhibitor among the compounds tested. Compounds in clinical use inhibited the DNA polymerase test only at high concentrations. The inhibitory activity of all compounds tested was increased when the MgCl2 content in the reaction mixture was lowered. UV absorption studies presented no evidence that this effect was due to complex formation of magnesium and the individual compounds. The therapeutic significance of these findings is not certain and needs further work.
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PMID:Inhibition of hepatitis B virus specific DNA polymerase by intercalating agents. 738 12

Ditercalinium chloride was originally synthesized for use as an anticancer drug and was then found to deplete mitochondrial DNA. Ethidium bromide is widely used to deplete mitochondrial DNA and produce mitochondrial DNA-less cell lines. Although ethidium bromide is used in the case of human cell lines, it frequently fails to deplete mitochondrial DNA in mouse cells. In contrast, ditercalinium chloride can deplete mitochondrial DNA in both mouse and human cells. However, little is known of the mechanisms by which ditercalinium chloride depletes mitochondrial DNA. Here, we show that ditercalinium chloride inhibits human DNA polymerase gamma activity as efficiently as does ethidium bromide. Ethidium bromide accumulates much less in mouse B82 cells, as compared with findings in human HeLa cells, whereas ditercalinium chloride accumulates in both to a similar extent. This poor accumulation of ethidium bromide may, in part, account for the resistance. Ethidium bromide distributes diffusely in the mitochondria of HeLa cells, while ditercalinium chloride distributes granularly and hence may be strongly associated with mitochondrial DNA. Each granular spot presumably represents one mitochondrial DNA nucleoid. In support of this idea, ditercalinium chloride co-localizes with Twinkle, a mitochondrial helicase and is assumed to associate with mitochondrial DNA. This close association of ditercalinium chloride with mitochondrial DNA may contribute to the mitochondrial DNA-depleting activity.
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PMID:Ditercalinium chloride, a pro-anticancer drug, intimately associates with mammalian mitochondrial DNA and inhibits its replication. 1267 81

Nucleoside analogs are associated with various mitochondrial toxicities, and it is becoming increasingly difficult to accommodate these differences solely in the context of DNA polymerase gamma inhibition. Therefore, we examined the toxicities of zidovudine (AZT) (10 and 50 microM; 2.7 and 13.4 microg/ml), didanosine (ddI) (10 and 50 microM; 2.4 and 11.8 microg/ml), and zalcitabine (ddC) (1 and 5 microM; 0.21 and 1.1 microg/ml) in HepG2 and H9c2 cells without the presumption of mitochondrial DNA (mtDNA) depletion. Ethidium bromide (EtBr) (0.5 microg/ml; 1.3 microM) was used as a positive control. AZT treatment resulted in metabolic disruption (increased lactate and superoxide) and increased cell mortality with decreased proliferation, while mtDNA remained unchanged or increased (HepG2 cells; 50 microM AZT). ddC caused pronounced mtDNA depletion in HepG2 cells but not in H9c2 cells and increased mortality in HepG2 cells, but no significant metabolic disruption in either cell type. ddI caused a moderate depletion of mtDNA in both cell types but showed no other effects. EtBr exposure resulted in metabolic disruption, increased cell mortality with decreased cell proliferation, and mtDNA depletion in both cell types. We conclude that nucleoside analogs display unique toxicities within and between culture models, and therefore, care should be taken when generalizing about the mechanisms of nucleoside reverse transcriptase inhibitor toxicity. Additionally, mtDNA abundance does not necessarily correlate with metabolic disruption, especially in cell culture; careful discernment is recommended in this regard.
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PMID:Absence of a universal mechanism of mitochondrial toxicity by nucleoside analogs. 1747 Jun 51