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)

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

The sulfated glycosaminoglycans chondroitin 4-sulfate, chondroitin 6-sulfate, keratan sulfate, dermatan sulfate, heparin, and glycosaminoglycan polysulfate are competitive inhibitors of the DNA-dependent RNA polymerase, the DNA-dependent RNA polymerase and the RNA-dependent DNA polymerase (reverse transcriptase). The unsulfated glycosaminoglycans chondroitin and hyaluronate are without any influence on the synthesis of DNA and RNA. The strongest inhibitor is a glycosaminoglycan polysulfate with four sulfate groups per disaccharide unit. It has the following inhibitor constants: DNA polymerase, Ki = 1.5 X 10(-6) M; RNA polymerase, Ki = 0.9 X 10(-6) M; reverse transcriptase, Ki = 1.1 X 10(-6) M. The inhibition is closely correlated to the degree of sulfation of the glycosaminoglycans. There is a relationship between the sulfate/hexosamine ratio and the degree of inhibition. The inhibition of the DNA and RNA synthesizing enzymes by sulfated glycosaminoglycans depends on the nature of the template. With double-stranded DNA as template, inhibition occurs only when sulfated glycosaminoglycans are added before or shortly after (30 s) initiation of the synthesis. There is no inhibition if the inhibitors are added after the onset of the synthesis. On the other hand, with a single-stranded template synthesis was blocked completely at each phase of reaction.
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PMID:Interactions of glycosaminoglycans with DNA and RNA synthesizing enzymes in vitro. 6 Nov 58

Procedures were established for the isolation and partial purification of DNA polymerase, RNA polymerase and poly(A) polymerase activities from the cytoplasm and nuclei of NIH-Swiss mouse embryos. Based on the elution pattern of these enzyme activities from DEAE-cellulose and phosphocellulose columns in Tris-HCl buffer, pH 8.0, the apparent basicities of the enzymes can be arranged as follows: cytoplasmic(C) poly(A) polymerase greater than (C)DNA polymerase beta greater than (C)DNA polymerase alpha and nuclear(N) poly(A) polymerase greater than (N)DNA polymerase greater than (N)RNA polymerase I greater than (N)RNA polymerase II. Twenty rifamycins, including rifamycin B, rifamycin S, rifamycin SV, and rifamycin SV derivatives, were examined for their ability to inhibit the above mentioned nucleic acid polymerizing enzymes and Simian sarcoma virus type I (SSV-1) reverse transcriptase. Rifamycin SV 3'-formyldiphenylhydrazone, rifamycin SV 3'-formyl-n-octyloxime (AF/013) and rifamycin SV 3'-formyldiphenylmethyloxime (AF/05) inhibited all the tested enzyme activities. Rifamycin SV 3'-formylpropylphenyloxime (AF/015) inhibited cellular nucleic acid polymerase activities but not SSV-1 DNA polymerase activity. Rifamycin SV 3'-formyldinitrophenylhydrazone (AF/DNFL) strongly inhibited reverse transcriptase activity but did not inhibit cellular DNA polymerase activities. AF/DNFI slightly inhibited RNA and poly(A) polymerase activities. Rifamycin SV 3'-formyldipropylhydrazone (AF/DPI) and 2,6-dimethyl-4-N-benzyldemethyl-rifampicin (AF/ABDMP) slightly inhibited reverse transcriptase activity but did not inhibit cellular nucleic acid polymerase activities. Active rifamycin derivatives inhibited enzyme reactions by interacting with the enzyme proteins. Nascent polynucleotide chain elongation continued although at a reduced rate in the presence of inhibitor. The addition of increasing concentrations of nonionic detergent (Triton X-100) to rifamycin-inhibited enzyme reactions fully restored enzyme activities. The presence of highly lipophilic 3'-side chains on active rifamycins and the reversibility of enzyme inhibition by Triton X-100 suggest that the tested nucleic acid polymerizing enzymes may have hydrophobic regions with which inhibitory rifamycins interact.
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PMID:Interaction of rifamycins with mammalian nucleic acid polymerizing enzymes. 6 93

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

Crude extracts of Escherichia coli selectively convert fd viral DNA and not phiX174 DNA to duplex DNA via a complex series of reactions one of which involves RNA polymerase. Reactions leading to formation of fd duplex-replicative (RFII) structures have been reconstituted with purified proteins from E. coli. Maximal synthesis requires the combined action of E. coli binding protein, DNA elongation factor I, DNA elongation factor II preparations (which are a mixture of dna Z and DNA elongation factor III), DNA polymerase III, DNA-dependent RNA polymerase, Mg2+, dATP, dGTP, dCTP, dTTP, and ATP, GTP, CTP, and UTP. In contrast to crude extracts of E. coli, purified protein fractions do not distinguish between fd DNA and phiX174 DNA in duplex DNA formation. The addition of crude fractions of E. coli to the purified components listed above selectively permits fd RFII formation and prevents phiX RFII formation. This selective inhibition was used as an assay to isolate proteins essential for this phenomenon; they include RNase H, discriminatory factor alpha, and discriminatory factor beta.
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PMID:Selective inhibition of in vitro DNA synthesis dependent on phiX174 compared with fd DNA. I. Protein requirements for selective inhibition. 14 Jan 66

Mammalian cells are known to synthesize DNA in discrete stages, the first of which seems to be the formation of DNA pieces 150--200 nucleotides in length that have a s20 value of about 4 S. We have reconstructed a system derived from HeLa cell nuclei that carries out RNA-primed initiation of the synthesis of small (4S) DNA fragments. This synthesis is resistant to high concentrations of alpha-amanitin and sensitive to antibody directed against RNA polymerase I, suggesting that this enzyme may be involved in the initiation step. The formation of small DNA fragments in this system also requires DNA polymerase alpha, heat-labile nuclear factor(s), and at least one other nuclear protein.
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PMID:Initiation of HeLa cell DNA synthesis in a subnuclear system. 28 14

Purified yeast DNA was transcribed by homologous RNA polymerases I and II and Escherichia coli RNA polymerase. Transcripts synthesized in vitro were analyzed by molecular hybridization with complementary DNA (cDNA) synthesized from yeast poly(A)-containing mRNA with viral reverse transcriptase and ribosomal DNA labeled in vitro by nick translation with E. coli DNA polymerase I. RNA synthesized by polymerase I and II in the presence of Mn2+ contained sequences complementary to cDNA and rDNA at a frequency consistent with random transcription of the template. Similarly, E. coli RNA polymerase synthesized an apparently random transcript in the presence of either Mn2+ or Mg2+. In contrast to these results, RNA polymerase I but not polymerase II transcripts were markedly enriched in sequences complementary to rDNA when transcription was carried out in the presence of Mg2+. The observed enrichment was 15-30-fold higher than observed for polymerase II or E. coli polymerase transcripts and is consistent with the transcript being comprised of 6-10% ribosomal sequences. These data strongly suggest that RNA polymerase I plays a critical role in selective transcription of ribosomal cistrons.
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PMID:Transcription of yeast DNA by homologous RNA polymerases I and II: selective transcription of ribosomal genes by RNA polymerase I. 31 52

A simple technique has been developed for isolating intracellular DNA and its bound proteins from uninfected and phage-infected bacteria. This technique, which utilizes aqueous salt concentrations in the physiological range, is based upon the fact that DNA exists in normal cell lysates in a stiff random coil conformation, and has an unusually large excluded volume to mass ratio. Such stiff coils display a unique combination of low sedimentation coefficient and large Stokes radius, enabling them to be separated rapidly from all other cellular components by successive centrifugal and gel permeation steps. Analysis of this purified intracellular DNA fraction from bacteriophage T4-infected Escherichia coli reveals mainly DNA and protein, with a small amount of RNA also present. Among the major proteins obtained are the DNA-dependent RNA polymerase of the host and the products of T4 genes rIIA, rIIB, and 32 (DNA-"unwinding" protein). Small amounts of the proteins coded by T4 genes 43 (DNA polymerase) and 42 (dCMP hydroxymethylase) have also been identified, in addition to at least 13 other phage-coded proteins of unidentified genes. Much of the phage-coded protein in the complex, including the gene 32 protein, does not exchange readily with the same protein exogenously added in the lysate.
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PMID:Intracellular DNA-protein complexes from bacteriophage T4-infected cells isolated by a rapid two-step procedure. Characterization and identification of the protein components. 32 53

In vitro DNA synthesis by yeast DNA polymerase I can be initiated by partially purified yeast RNA polymerases in the presence or absence of rNTPs. Homogeneous yeast RNA polymerase I initiates DNA synthesis by yeast DNA polymerase I on single-stranded DNA templates only in the presence of all four rNTPs. A protein capable of initiating enzymatic DNA synthesis on single-stranded DNA in the absence of rNTPs has also been separated from partially purified yeast RNA polymerase I fractions. Analysis of the RNA polymerase I initiated replication products of phage fd DNA on alkaline sucrose gradients showed noncovalent linkage between the newly synthesized DNA and the template. Isopycnic analyses of the ribonucleotide initiated fd DNA replication products demonstrated covalent linkage between the initiator RNA and newly synthesized DNA. Results from 32P-transfer experiments confirmed the covalent linkage between RNA and DNA chains and showed the presence of all four ribo- and deoxyribonucleotides at the RNA--DNA junctions. The ribonucleotide found most frequently at the RNA--DNA junction is uridylate and the purine deoxynucleotides occur more frequently than pyrimidine deoxynucleotides.
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PMID:Initiation of enzymatic DNA synthesis by yeast RNA polymerase I. 35 89

The interaction of pyridoxal, pyridoxal-5'-mono-, di- and triphosphate with certain enzymes of polynucleotide synthesis (DNA-dependent RNA polymerase, DNA-dependent DNA polymerase I and polynucleotide phosphorylase from Escherichia coli and terminal deoxyribonucleotide transferase from calf thymus) was studied. All compounds tested was found to be reversible and competitive inhibitors of these enzymes. The reduction of the enzyme-inhibitor complex with NaBH4 gives rise to the complete irreversible inhibition of the enzymes under study. The comparison of the inhibition constants for pyridoxal and its phosphorylated derivatives with those for mono-, di- and triphosphates of nucleosides was carried out for the enzymes. The results obtained suggest that the modified epsilon-amino-group of lysine residue should be localized at the catalytic site in the vicinity of the pyrophosphate binding area of an enzyme.
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PMID:[Interaction of oligophosphates of pyridoxal with certain enzymes of polynucleotide synthesis]. 38 98


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