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)

According to our data native Tth DNA polymerase displays higher reverse transcription activity than Taq DNA polymerase. This allows one to use Tth DNA polymerase in the complete reaction of reverse transcription and amplification (RT/PCR). We used this enzyme to synthesize the interleukine (IL-2 alpha) RNA template synthesized by the RT/PCR method in vitro. The conditions for RNA IL-2 alpha detection were optimized. The maximum yield of the specific product was obtained at pH 8.5-9.0. The influence of bivalent cations on the efficiency of RT reaction of coupled RT/PCR can be expressed as: Mn2+ > or = Cu2+ > Mg2+ > Cd2+ >> Co2+. The optimal ratio is 1.25-1.88 for Mn2+/dNTPs and 1.88-2.5 for Cu2+/dNTPs and Cd2+/dNTPs. The maximum yield of the RT/PCR product is found at Mg2+/dNTPs = 3.75. When Mn2+ is used instead of Mg2+ in the PCR reaction the efficiency of RT/PCR decreases. The RT/PCR method embracing thermostable Tth DNA-polymerase provides detection of 10(3) copies of RNA IL-2 alpha. An efficient method of the express-diagnostics of MDR-1 gene expression by coupled RT/PCR using Tth DNA polymerase is described.
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PMID:[Use of thermostable DNA polymerase from Thermus thermophilus KTP in a combined reverse transcription and amplification reaction of detecting interleukin 2alpha RNA and determining expression of the multidrug resistance gene (MDR-1)]. 747 58

The RT/PCR method was applied to study a possible use of Tth DNA-polymerase for coupled reaction of reverse transcription and polymerase chain reaction (RT/PCR) on the CD-4 receptor mRNA template in the total cellular RNA. The conditions for detecting the CD-4 receptor mRNA were optimized. The pH-optimum for RT reaction was 8.8. The influence of Mn2+, Cu2+, Co2+, and Cd2+ cations in RT and PCR reaction was investigated. The efficiency of the RT reaction was shown to be the highest in the presence of Mn2+ (optimal concentration 1 mM). At Mn2+ concentration > or = 3 mM complete inhibition of RT/PCR was observed. The Tth DNA polymerase in RT/PCR was shown to be more effective than Taq DNA polymerase. The Tth DNA polymerase allows observation of the specific product in the gel containing ethidium bromide using 20 ng of the total RNA. High sensitivity and specificity of RT/PCR performed with the Tth DNA polymerase allow its wide application in the detection, quantitative analysis and cloning of cellular and viral RNAs.
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PMID:[Use of thermostable DNA polymerase from Thermus thermophilus KTP in a combined reverse transcription and amplification reaction for detecting CD4 receptor mRNA]. 747 59

Repair of quercetin-induced single-strand breaks of DNA was studied in vitro using cell free extract from GM 00637D cells, a human cell line. Single-strand breaks were introduced into DNA by the treatment of closed circular, superhelical form of pBR322 plasmid DNA with quercetin and Cu(II). Repair of these breaks was demonstrated by agarose gel electrophoresis after incubating damaged DNA with cell extract, DNA polymerase I (klenow fragment of DNA polymerase), four deoxynucleotide triphosphates, ATP and T4 DNA ligase. The present results suggested that 1) the exonuclease is involved in the initiation of repair of quercetin-induced single-strand breaks by removing the 3' ends of quercetin damaged DNA and 2) oxygen free radicals are involved in quercetin-induced DNA strand scission.
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PMID:Repair of quercetin-induced single-strand breaks by a cell free system. 801 39

Heterocyclic thiosemicarbazones, thioureas and 2-substituted pyridine N-oxides as well as representative nickel, cobalt and copper complexes were shown to be potent antineoplastic/cytotoxic agents. The cytotoxicity was demonstrated against single cell leukemia as well as cell lines derived from solid tissue (colon adenocarcinoma, HeLa, KB, skin, bronchogenic lung, bone osteosarcoma and glioma). In L1210 cells, DNA synthesis and subsequently RNA synthesis were particularly inhibited by the agents. IMP dehydrogenase activity and thus purine de novo synthesis was reduced significantly by the agents. Dihydrofolate reductase, ribonucleoside reductase, nucleoside kinase and DNA polymerase alpha activities were inhibited by the agents. d(NTP) pool levels were reduced by most of the agents. DNA strand scission was present with all of the derivatives; however, there was no evidence of intercalation, cross linking or alkylation/binding to bases of DNA. This new group of compounds may offer novel exploratory derivatives for future investigations in the treatment of cancer.
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PMID:The cytotoxicity of heterocyclic thiosemicarbazones and their metal complexes on human and murine tissue culture cells. 849 Feb 2

Analysis of 94 kb of DNA, located between map positions 88 and 182 kb in the 330-kb chlorella virus PBCV-1 genome, revealed 195 open reading frames (ORFs) 65 codons or longer. One hundred and five of the 195 ORFs were considered major ORFs. Twenty-six of the 105 major ORFs resembled genes in the databases including three chitinases, a chitosanase, three serine/threonine protein kinases, two additional protein kinases, a tyrosine protein phosphatase, two ankyrins, an ornithine decarboxylase, a copper/zinc-superoxide dismutase, a proliferating cell nuclear antigen, a DNA polymerase, a fibronectin-binding protein, the yeast Ski2 protein, an adenine DNA methyltransferase and its corresponding DNA site-specific endonuclease, and an amidase. The genes for the 105 major ORFs were evenly distributed along the genome and, except for one noncoding 1788-nucleotide stretch, the genes were close together. Unexpectedly, a 900-bp region in the 1788-bp noncoding sequence resembled a CpG island.
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PMID:Analysis of 94 kb of the chlorella virus PBCV-1 330-kb genome: map positions 88 to 182. 861 77

Uric acid is present in human plasma in relatively high concentrations and is considered to be a natural physiological antioxidant. We have earlier shown that in the presence of Cu(II) and molecular oxygen, uric acid causes strand breakage in DNA. In this article, we show that uric acid fluorescence is quenched by addition of DNA, indicating the formation of uric acid-DNA complex. Uric acid-Cu(II)-mediated DNA strand scission is capable of bacteriophage inactivation and such inactivation is mediated through reduction of Cu(II) to Cu(I) and the generation of oxygen-derived radicals. It is indicated that the DNA breakage is repaired in E. coli and involves the repair of DNA polymerase.
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PMID:DNA breakage by uric acid and Cu(II): binding of uric acid to DNA and biological activity of the reaction. 888 66

The activity of some nuclear enzymes associated with DNA repair was examined following aflatoxin B1 administration in rats maintained on different levels of dietary copper. Induction of poly(ADP-ribose) polymerase, DNA polymerase beta and DNA ligase was found to be significantly higher in copper-deficient rats. Copper supplementation, even at marginal doses, was able to bring down the induction to the level observed in normal rats. The results emphasize the protective role of copper against the DNA damaging effects of aflatoxin B1.
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PMID:Modulation by dietary copper of aflatoxin B1-induced activity of DNA repair enzymes poly (ADP-ribose) polymerase, DNA polymerase beta and DNA ligase. 889 34

A series of 2-acetyl-pyridyl-4N-substituted thiosemicarbazones copper(II) complexes was evaluated for their cytotoxic mode of action in a variety of human and rodent tumor cell cultures. It was determined that these compounds may induce cytotoxicity by affecting several metabolic pathways including a reduction in de novo purine synthesis, and inhibition of IMP dehydrogenase, and DNA polymerase alpha activities. Selected compounds also demonstrated the ability to inhibit L1210 DNA topoisomerase II activity at micromolar concentrations. These agents were able to antagonize etoposide-induced formation of cleavable complexes as measured by K+/SDS precipitation and in vitro cleavage reactions.
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PMID:The cytotoxicity of copper(II) complexes of 2-acetyl-pyridyl-4N-substituted thiosemicarbazones. 989 58

A study of di- and trihydroxyalkylbenzenes and bis(dihydroxyalkylbenzenes) revealed that several compounds were capable of both mediating Cu(2+)-dependent DNA cleavage and strongly inhibiting DNA polymerase beta. The most potent DNA polymerase beta inhibitors were bis(dihydroxyalkylbenzenes) 5 and 6; compounds 3 and 4 were also reasonably potent. The length of the alkyl substituent was found to be a critical element for DNA polymerase beta inhibition, since compounds 1 and 2 had shorter substituents than 3 and were completely inactive. Lineweaver-Burk plots revealed that 3, 4, and 6 exhibited mixed inhibition of DNA polymerase beta with respect to both activated DNA and dTTP. Unsaturated bis(dihydroxyalkylbenzene) 5 was a pure noncompetitive inhibitor with respect to both substrates and associated avidly with the enzyme whether or not it was in complex with its substrate(s). Copper(II)-mediated DNA cleavage was the most pronounced for the trihydroxyalkylbenzene 3, consistent with an earlier report [Singh, U. S., Scannell, R. T., An, H., Carter, B. J., and Hecht, S. M. (1995) J. Am. Chem. Soc. 117, 12691-12699]. Unsaturated bis(dihydroxyalkylbenzene) 5 was the next most active DNA cleaving agent, followed by the dihydroxyalkylbenzene 4. The saturated bis(dihydroxyalkylbenzene) (6) did not cleave DNA well in a cell-free system under the conditions studied but nonetheless potentiated the effects of bleomycin to the greatest extent in cell culture studies. Interestingly, compound 5 produced a reduction in the numbers of viable cells when incubated in the presence of bleomycin and a further reduction in the numbers of viable cells in the presence of both bleomycin and Cu(2+). The same effect was noted to a lesser extent for compound 3 but not for 4 or 6.
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PMID:Naturally occurring alkylresorcinols that mediate DNA damage and inhibit its repair. 1069 11

The interaction of DNA polymerase from Thermus thermophilus B35 (Tte-pol) with deoxynucleoside triphosphates in the presence of different divalent metal ions has been studied. DNA synthesis and competitive inhibition of the polymerase reaction by non-complementary dNTPs are described with corresponding kinetic schemes. The co-factor properties of some metals (Mg2+, Mn2+, Co2+, Ni2+, Cu2+, Ca2+, Cd2+, and Zn2+) were investigated, and their activating concentration ranges were determined. It was found that kcat values are significantly decreased and Km values slowly decrease when Mn2+ displaces Mg2+. The value of Kd for DNA template-primer is Me2+-independent, whereas Kd values for non-complementary dNTPs decrease in the presence of Mn2+. Tte-pol processivity but not DNA synthesis efficiency is Me2+-type independent.
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PMID:Thermostable DNA polymerase from Thermus thermophilus B35: influence of divalent metal ions on the interaction with deoxynucleoside triphosphates. 1085 Oct 40


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