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

---

Query: EC:2.7.7.6 (RNA polymerase)
34,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The properties of poly(G) polymerase and poly(A) polymerase activities in the DNA-dependent RNA polymerase [nucleosidetriphosphate: RNA nucleotidyltransferase EC 2.7.7.6] I fraction from cauliflower (Brassica oleracea var. botrytis) were comparatively investigated. The pH optimum, the effect of ionic strength, the effect of substrate concentration on the rate of synthesis, the effect of divalent metal ion concentration, and the time course of synthesis at different temperatures were all different for the three polymerase activities. The enzyme fraction preferentially utilized denatured DNA. Synthetic poly(C) and poly(U) were more effectively utillized for the synthesis of polyguanylate and polyadenylate, respectively. Further, it was found that poly(G) and poly(A) formed in vitro by the enzyme fraction had chain length of 25-28 and 84-89 nucleotides, respectively, and that poly (adenylate-gluanylate) chain was hardly formed when ATP and GTP were added together as substrates in the same reaction medium.
...
PMID:Comparative studies on polyguanylate polymerase and polyadenylate polymerase activities in the DNA-dependent RNA polymerase I fraction from cauliflower. 0 54

The alkoxybenzophenanthridine alkaloids (coralyne acetosulfate, fagaronine chloride, and nitidine chloride) have been reported to possess antileukemic activity in mice. These compounds were tested for inhibition of reverse transcriptase activity of an RNA tumor virus and DNA polymerase, RNA polymerase, and polyadenylic acid polymerase activities of NIH-Swiss mouse embryos. Reverse transcriptase and DNA polymerase activities were strongly inhibited by these antileukemic alkaloids, whereas RNA polymerase and polyadenylic acid polymerase activities were only moderately affected. Viral and cellular DNA polymerase activities were potently diminished by the alkaloids when poly[d(A-T)], poly(dA)-oligo(dT), and poly(rA)-oligo(dT) template primers were used in the reaction mixture; however, no inhibition of enzyme activity was obtained with poly(rC)-oligo(dG) as template primer. These results suggest that alkoxybenzophenanthridine alkaloids inhibit DNA polymerase activity by interaction with A:T base pairs of the template primer.
...
PMID:Inhibition of mammalian and oncornavirus nucleic acid polymerase activities by alkoxybenzophenanthridine alkaloids. 5 19

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.
...
PMID:Interaction of rifamycins with mammalian nucleic acid polymerizing enzymes. 6 93

Noradrenaline added to perfused rabbit heart previously perfused with labelled precursors causes, after 2.5 and 5.0 min, a general increase of specific radioactivity or RNA in subcellular fractions, but no augmentation of acetylation of F2a2 and F2a1 histone fractions and no stimulation of DNA-dependent RNA polymerase activities. Synthesis of spermidine and spermine is enhanced at 10.0 min of treatment, when there is also a fall in specific radioactivity of RNA. The cytoplasmic Mn2+-stimulated polyadenylate polymerase activity is strongly enhanced 30s to 2.5 min after injection of noradrenaline or of dibutyryl cyclic AMP. Both the cyclic nucleotide and noradrenaline have no influence in vitro on the polyadenylate polymerase reaction.
...
PMID:Modifications of major aspects of myocardial ribonucleic acid metabolism as a response to noradrenaline. Behaviour of polyadenylate polymerase and ribonucleic acid polymerase, acetylation of histones and rate of synthesis of polyamines. 20 85

Three RNA polymerase activities were found and associated with purified Pichinde virus, a member of the Arenaviridae. A heat-labile polymerase activity which required all four ribonucleoside triphosphates for optimal activity co-sedimented on sucrose gradient centrifugation with the viral ribonucleoprotein complex from detergent-disrupted virus preparations. This enzyme synthesized heteropolymers which represented about 23% of the genome RNA as determined by nucleic acid hybridization. Two relatively heat-stable polymerase activities which differed in their cation requirement and substrate specificity were recovered with the virus-associated ribosomes. These polymerase activities synthesized homopolymers of limited chain length: in the presence of 10 mM Mg2%, polyuridylic acid was made, whereas in the presence of 1 mM Mn2%, polyadenylic acid was made. The addition of complementary RNA synthesized with the viral transcriptase in vitro to the reaction mixture containing the polyadenylic acid polymerase activity resulted in the terminal addition of polyadenylic acid to the complementary RNA. The possible function of the ribosome-associated polymerase activities in the replication of the virus is discussed.
...
PMID:Distinctive RNA transcriptase, polyadenylic acid polymerase, and polyuridylic acid polymerase activities associated with Pichinde virus. 22 33

Mn2+-dependent poly(A) polymerase activity tested in isolated rat liver nuclei is unchanged both in the absence and presence of exogenous poly(A) 30 min. after administration of a dose of alpha-amanitin that inhibits DNA-dependent RNA polymerase B. Longer times of treatment cause poly(A) polymerase to drop to 50% in the absence of poly(A) and to increase almost twice in its presence.
...
PMID:[Effect of administration of alpha-amanitine on Mn2+ - dependent poly-A-polymerase in rat liver nuclei]. 23 4

Avian erythroid cells were separated into five developmental stages by sedimentation on discontinuous isotonic albumin gradients. Solubilized enzyme activities from whole cells were partially purified and characterized by ion exchange and ion filtration chromatography and velocity sedimenttation analysis. Three nucleotide polymerase types were investigated: (a) DNA-dependent RNA polymerases; (b) RNA-dependent terminal ribonucleotidyltransferases, and (c) DNA-dependent DNA polymerases. The two characteristic forms of eucaryotic DNA-dependent RNA polymerases, polymerase I (nucleolar) and polymerase II (nucleoplasmic), were identified. Polymerase III was only marginally detectable even in the earliest developmental populations. At least two species of RNA-dependent terminal ribosyltransferases were present. One apparently was the poly(A) polymerase observed in other systems. The other terminal transferase was present in two chromatographic forms, required an RNA primer, and used UTP and/or CTP as particularly efficient substrates. Three DNA polymerase activities were resolved, two of which were characteristic of the alpha and beta DNA polymerases described in other eucaryotic systems. The third polymerase was not the gamma polymerase but a separate entity. Poly(dC)-dependent RNA polymerase activity, associated with the alpha polymerase, was relatively enriched in the third DNA polymerase species. The activity levels of the nucleotide polymerases were monitored as a function of red cell maturation. Characteristic declining patterns of activity were obtained for each enzyme which correlate well with the synthetic rates of their in vivo products where these are known. These results correlate well with the synthetic rates of their in vivo products where these are known. These results are consistent with the postulate that the general transcriptive and replicative control processes operating during development may involve changes in the level of the requisite polymerases.
...
PMID:Nucleotide polymerases in the developing avian erythrocyte. 83 21

DNA-dependent RNA polymerase, DNA-Dependent DNA polymerase, and terminal riboadenylate transferase (TRT) activities have been measured after DEAE-Sephadex chromatography of whole cell extracts prepared from eggs and staged embryos of the urchin, Stronglyocentrotus franciscanus. Activity of each of these three polymerase classes is present in the egg, and the total activity per embryo is constant throughout embryogenesis to the pluteus stage (approximately 1000 cells). Thus the egg appears to contain sufficient DNA polymerase, RNA polymerase, and TRT TRT for embryogenesis. The increases in the synthesis of DNA, RNA and polyadenylated RNA tracts observed after fertilization must be due to the activation of the preexisting egg enzymes. Separation of the egg into nucleate and anucleate halves demonstrates that the RNA polymerases are not restricted to the egg nucleus. During development, the enzymes become progressively more associated with the cell nucleus. The egg extracts contain low activities (approximately 6% total) of RNA polymerase II as measured by sensitivity to alpha-amanitin. This is confirmed by resolution of the RNA polymerase forms I, II, and III by gradient sievorptive elution on DEAE-Sephadex. Later stage embryos contain more nearly equal activities of RNA polymerase, I, II, and III, although the total RNA polymerase activity per embryo is not changed. Additionally, two chromatographicallly distinct species of RNA polymerase III are detected, one of which is observed only in later stages. Thus interconversion of enzymes via addition of new subunits or coordinate synthesis and loss of enzyme species must occur.
...
PMID:Nucleic acid polymerizing enzymes in developing Strongylocentrotus franciscanus embryos. 98 54

Factors affecting the inhibition of RNA polymerase II from rat liver by the O-n-octyloxime of 3-formylrifamycin SV (AF/013) were investigated. Using either native or denatured calf-thymus DNA as template, almost complete inhibition of RNA polymerase II was observed when AF/013 was added directly to the enzyme. Considerable resistance to AF/013 was observed when RNA polymerase II was preincubated with denatured DNA at either 0 or 37 degrees. However, under similar conditions, no resistance was observed when enzyme was preincubated with native DNA. Only when AF/013 was added to the ongoing reaction using native DNA did a resistance to AF/013 occur. The inhibition of RNA polymerase II by AF/013 was competitive with respect to all four nucleoside triphosphate substrates. The inhibition by AF/013 remaining after enzyme-DNA complex formation also appeared competitive with nucleoside triphosphate levels. The effect of exogenous protein (bovine serum albumin, BSA) on the inhibition of RNA polymerase II was also investigated. BSA reduced the extent of inhibition by AF/013, but did not alter the competitive nature of inhibition. Concurrently, the inhibition of highly purified nuclear poly(A) polymerase from rat liver, a template independent enzyme which incorporates AMP in a chain elongation reaction, was examined. As in the case of RNA polymerase, poly(A) polymerase was inhibited by AF/013 in a manner competitive with the nucleoside triphosphate substrate. The competitive nature of inhibition of RNA polymerase by AF/013 with respect to all four nucleoside triphosphate substrates, before and after enzyme-DNA complex formation, as well as the competitive nature of inhibition of poly(A) polymerase with respect to ATP tend to indicate that the major effect of AF/013 on RNA polymerase II is at the level of the substrate binding as opposed to a specific inhibition of initiation.
...
PMID:Mechanism of inhibition of RNA polymerase II and poly(adenylic acid) polymerase by the O-n-octyloxime of 3-formylrifamycin SV. 116 99

A nuclear poly(A) polymerase has been isolated from oviducts of immature quails. It could be purified 4300-fold. The enzyme depends specifically on ATP as substrate and requires Mg2+. The most effective primer for the enzyme is a polynucleotide, isolated from oviduct tissue. A poly(A) sequence to a maximum of 60 AMP residues is covalently linked per primer molecule. The poly(A)-rich product of the enzymatic reaction can be annealed to oligo(dT)-cellulose. The purest fraction does not contain any detectable poly(A)-degrading enzyme activity. Only very low activities of RNA polymerase are present. The poly(A polymerase activity in the assay with ATP is reduced by the ATP analogue, beta, lambda-ATP-methylene-diphosphonate. Both K-m and V are lowered. The ATP analogue is incorporated to a smaller extent into the poly(A) sequence, synthesized by the enzyme. Several other analogues of adenine, adenine nucleosides and adenine nucleotides are without effect on the enzymatic reaction. By these properties poly(A) polymerase can be distinguished from RNA polymerases form I and form II, isolated from the same tissue. Actinomycin D and alpha-amanitin failed to inhibit poly(A) polymerase activity. The activity of poly(A) polymerase has been determined during primary stimulation with the estrogen analogue diethylstilbestrol (daily injection for 5 days), after withdrawal of the hormone for 17 days and after secondary stimulation with the hormone analogue. The enzyme activity does not change during primary stimulation, withdrawal of the hormone or secondary stimulation. However the activity of a poly(A) degrading enzyme, localized in the nucleus, is reduced in oviducts from hormone-treated quails.
...
PMID:Poly(A) polymerase in quail oviduct. Changes during estrogen induction. 116 81


1 2 3 4 5 6 Next >>

---