共查询到20条相似文献,搜索用时 31 毫秒
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Neomycin inhibits DNA dependent DNA and RNA synthesis catalyzed by DNA polymerase I and RNA polymerase from . The effect of the antibiotic is more pronounced towards DNA synthesis. The inhibition of DNA synthesis is competitive with template DNA, does not reverse with excess deoxynucleoside triphosphate, Mg2+ or enzyme DNA polymerase I. Neomycin does not reduce the number of potential 3′ -OH end or primer. It seems to shorten the size of the newly formed polynucleotide. 相似文献
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Evidence for template-specific sites in DNA polymerases 总被引:3,自引:0,他引:3
S L Marcus M J Modak L F Cavalieri 《Biochemical and biophysical research communications》1974,56(2):516-521
Using rabbit hemoglobin messenger RNA as template, polymerase I produces poly (dT), poly (dA)·(dT) and antimessenger DNA products. Mild heating of the enzyme causes a differential loss in activity as indicated by three rates of inactivation for the three types of synthesis. Heat inactivation studies have also been carried out with DNA polymerases from oncogenic RNA viruses and mammalian sources using various homopolymer-oligomer pairs as primertemplates. In general, for any given enzyme these synthetic primer-templates reveal different extents of inactivation of the polymerase. These findings may be interpreted to suggest a) that the binding of DNA polymerase to various primer-templates produces conformational changes in the enzyme which are dependent on the type of template bound, or b) that many, if not all, DNA polymerases have different subsites for different templates. 相似文献
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The RNA synthesis and poly(A) synthesis catalyzed by cauliflower RNA polymerase are stimulated by an addition of polyethylenimine (PEI) at a low concentration to the reaction medium. Evidence is presented that PEI exerts its stimulative effect on a reaction coexisting of enzyme, template, and substrate, and not on the template or enzyme alone. 相似文献
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Qβ replicase, RNA polymerase, and T7 RNA polymerase are inhibited by low concentrations of the dye aurintricarboxylic acid (ATA). In each case initiation by the enzyme was preferentially inhibited. The elongation of initiated polynucleotide chains by Qβ replicase was insensitive to ATA in the range of concentrations required to inhibit initiation. Treatment of Qβ replicase, RNA polymerase and repressor with ATA prevented enzymemediated binding of the templates to nitrocellulose filters. We propose that the inhibitor combines with the template binding site of these proteins to prevent initiation. 相似文献
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Activation of the template activity of isolated rat liver nuclei for DNA synthesis and its inhibition by NAD 总被引:6,自引:0,他引:6
The template activity of isolated rat liver nuclei for DNA synthesis assayed with DNA polymerase was found to be dependent upon the presence of Ca2+ or Mg2+ in the incubation medium. DNA was prepared from isolated nuclei subjected to conditions which activated the template and centrifuged in an alkaline sucrose gradient. The distribution profile showed that smaller fragments were formed, suggesting enhancement of endonucleolytic activity. When isolated nuclei were incubated with NAD to induce poly(adenosine diphosphate ribose) formation and were subjected to the activation conditions, the template for DNA synthesis remained unchanged. The distribution profile in an alkaline sucrose gradient of DNA prepared from these nuclei and control nuclei was identical. The present findings suggest that the template-activating system for DNA synthesis was blocked when isolated nuclei were treated with NAD . 相似文献
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Susan Peacock Nathan Brot Herbert Weissbach 《Biochemical and biophysical research communications》1983,113(3):1018-1025
Using the plasmid pNF1337 as template, a mRNA preparation has been obtained that directs the synthesis of fMet-Val, the N-terminal dipeptide of the β subunit of RNA polymerase. RNA polymerase holoenzyme specifically inhibits the mRNA-directed synthesis of fMet-Val showing that the autoregulation by RNA polymerase of β,β′ synthesis is at the level of translation. L factor ( gene product) stimulates the synthesis of fMet-Val from a DNA template but not from mRNA. Rifampicin has no effect on the mRNA-directed synthesis of fMet-Val or the ability of RNA polymerase to inhibit fMet-Val synthesis. 相似文献
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Transcription of chromatin by human RNA polymerase 总被引:3,自引:0,他引:3
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