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

The effects of 4'-epi-daunorubicin, 4'-epi-adriamycin, and the corresponding beta anomers on the in vitro activity of Escherichia coli DNA polymerase I and RNA polymerase were determined and compared with the effects of the parent compounds. The observed effects parallel the cytotoxic activities, assayed by inhibition of mouse embryo fibroblast proliferation, and the inhibitory activities on DNA synthesis in cultured cells. The data indicate that the inverted configuration at position 1 of the amino sugar results in a markedly reduced biological activity. This conclusion is also substantiated by the data obtained with the beta anomer of adriamycin. A preliminary investigation on the binding properties of these derivatives suggests that the inverted configuration at C-1' produces a significant decrease in the binding to DNA. In contrast, epimerization at position 4' did not produce any significant change in activity. The relationship between biological and biochemical activity and DNA binding properties of the tested compounds are discussed with particularly reference to antitumor activity.
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PMID:Relationship between activity and amino sugar stereochemistry of daunorubicin and adriamycin derivatives. 77 33

In vitro inhibitions by coumermycin A1 of DNA and RNA synthesis in toluenized cells were studied. In a sensitive strain, 50% inhibitions of replication and transcription were observed at 0.035 and 0.600 mug/ml, respectively. DNA synthesis in a toluenized-resistant mutant was 50% inhibited at 0.140 mug/ml of coumermycin A1, whereas RNA synthesis was unaffected at all concentrations tested. Studies with a mixture of toluenized-sensitive and -resistant bacteria ruled out the presence of a diffusable activator or inhibitor of coumermycin A1 action. Density label studies with toluenized pol A+ and pol A- strains indicated that replicative DNA synthesis was specifically inhibited, in agreement with the in vivo studies in the preceding paper of this issue (Ryan, M. J. (1976), Biochemistry 15). Highly purified Escherichia coli DNA polymerase III and RNA polymerase both were inhibited by this antibiotic. However, the high concentrations necessary for these inhibitions suggest that they are not biologically relevant. No interaction between DNA and coumermycin A1 was observed with the following analytical procedures: ultraviolet difference spectra, DNA absorbance-temperature transitions, equilibrium buoyant density centrifugation, and DNA cross-linking determinations.
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PMID:Coumerimycin A1: A preferential inhibitor of replicative DNA synthesis in Escherichia coli. II. In vivo characterization. 78 23

Pituitary growth hormone (GH) has considerable potential as an anabolic agent in animal production. For example, pigs treated with GH will grow faster (i.e. deposit protein), require less feed per unit of body weight gain, and will have less carcass fat than untreated animals. Lactating cows will produce more milk with less feed. It is likely, though not completely established, that young cattle will also respond to GH treatments. Most of the information on the mode of action of GH has been obtained with laboratory rather than farm animals. The hormone affects almost all aspects of metabolism although the specific mechanism for these effects is still not understood. Stimulation of protein accretion is reflected by increased nitrogen retention and incorporation of radioactive amino-acids into tissue proteins. An increased rate of protein synthesis is thought to be a result of enhanced ability of ribosomes to translate messenger RNA. GH increases polyamine synthesis by increased ornithine decarboxylase activity; RNA synthesis by increasing RNA polymerase and DNA synthesis by increased DNA polymerase. Cell division is stimulated in several tissues (e.g. muscle and lymphoid tissue). In vivo GH lowers the respiratory quotient indicating an increased oxidation of fatty acids. The numbers of fat cells do not change but the fat cells are reduced in size. The stimulating effects of GH on skeletal tissue, and perhaps other tissues as well, is mediated by the formation of at least three peptides called somatomedins. GH is a protein with a molecular weight of about 22,000 and contains 191 amino-acid residues. The amino-acid sequence varies with the species. GH isolated from one species is not always effective in a different species. Use of GH isolated from pituitaries does not appear to be economically feasible. A chemical synthesis for human GH has been accomplished. However, biological activity equivalent to the native hormone has not been unequivocally established. Synthesis of bovine or porcine GH is feasible but will be expensive. A partial sequence of GH with 39 amino-acid residues has some biological activity. Synthesis of this shorter peptide would be considerably less expensive. Since proteins generally are not active orally, an economic procedure for prolonged parenteral administration would have to be devised. Althernative approaches would be the stimulation of endogeneous production of GH with hypothalmic GH releasing factor. This factor has not been identified but is probably a small peptide. Agents such as arginine, DOPA, and prostaglandins, which are known to stimulate GH release under some conditions, could also be considered. Another approach would be the implantation of sparganum from the spirometra family (a flatworm). This treatment is known to mimic GH effects in the rat. Implantation of a GH producing tumour could also be considered. Clearly these latter suggestions are quite speculative and would present some obvious problems...
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PMID:Role of growth hormone in improving animal production. 78 72

The 5-thio and 5-methylmercurithio derivatives of UTP, dUTP and dCTP have been synthesized and tested as substrates for nucleic acid polymerases. The 5-thio-nucleotides were polymerized inefficiently by both RNA polymerase and DNA polymerase I of Escherichia coli. The 5-methylmercurithio derivatives of dUTP and dCTP were, however, utilized by DNA polymerase I, an enzyme insensitive to mercurial compounds, although they were potent inhibitors of all other polymerases tested. While polymers containing the 5-thio substituent possess structural abnormalities, most likely interstrand disulfide bridges, polymers containing 5-methylmercurithio groups appear normal. The latter polynucleotides are readily separated from non-sulfated polymers by chromatography on mercuriagarose.
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PMID:The synthesis and enzymatic polymerization of 5-thio- and 5-methylmercurithio-pyrimidine nucleotides. 79 73

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.
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PMID:Nucleotide polymerases in the developing avian erythrocyte. 83 21

In vaccinia virus infected cells the appearance of a late enzyme RNA polymerase was prevented by MPB, an inhibitor of nucleolar RNA synthesis, although inductions of the early enzymes thymidine kinase and DNA polymerase were not affected. It is inferred the nucleoli may be involved in the replication of vaccinia virus.
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PMID:Failure of poxvirus replication in the presence of an inhibitor of nucleolar RNA synthesis. 85 97

The nonhistone proteins of Ehrlich ascites tumor chromatin have been separated into a loosely bound and two tightly bound protein fractions by sequential extraction of chromatin with 0.35 M NaCl and 2 M NaCl:5 M urea. The nonhistone proteins thus obtained were examined for their chemical composition and distribution of DNA polymerase, RNA polymerase, and protein kinase activities. In addition, the effect of these nonhistone proteins on transcription of DNA in vitro has been determined. The results indicate that these nonhistone proteins, fractionated on the basis of their extractability, exhibit varied compositional characteristics and play different functional roles in the synthesis of DNA and RNA and in the possible control of gene activity.
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PMID:A comparison of the loosely bound and tightly bound nonhistone proteins from Ehrlich ascites tumor chromatin. 97 79

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.
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PMID:Nucleic acid polymerizing enzymes in developing Strongylocentrotus franciscanus embryos. 98 54

DNA alpha-polymerase has been partially purified from nuclei of cultured chic, fibroblasts and separated on phosphocellulose columns into two distinct activities designated DNA polymerases alpha(a) and alpha(b), respectively. The enzyme preparations were devoid of activities of DNA beta,gamma-polymerases terminal deoxyribonucleoside transferase, DNase, DNA-dependent RNA polymerase, and phosphatase. DNA polymerases alpha(a) and alpha(b) both having molecular weights of 160 000, constitute 35-50 and 65-50%, respectively, of the activity of alpha-polymerase in the nucleus. These enzymes differ in their requirements for maximal activity, their relative ability to copy oligo(dG)-poly(dC), their response to ribonucleoside triphosphates, and their kinetics of heat inactivation. When the properties of alpha polymerases derived from early or late passage cultures have been compared, no difference could be detected as a function of cell age in the specific activities of the polymerases in crude cell extracts, their chromatographic behavior on diethylaminoethylcellulose and phosphocellulose columns, and their relative abilities to utilize single deoxyribonucleoside triphosphates with activated DNA template. On the other hand, both enzymes become partially heat labile in aging cells. Also, the activity of DNA polymerase alpha(a) from young cells was stimulated by 2--10 mM adenosine or cytidine triphosphates, whereas the same enzyme from old cultures was inhibited by these agents. Conversely, these ribonucleoside triphosphates inhibited the activity of polymerase alpha(b) in young cells but slightly stimulated this enzyme derived from senescent fibroblasts. In addition, the relative ability of DNA polymerase alpha(a) to copy oligo(dG)-poly(dC) decreased in aged cells, whereas that of DNA polymerase alpha(b) increased. We have also observed significant differences in the effects of potassium chloride and N-ethylmaleimide on the activity of DNA polymerase alpha(a) from old cells as compared to young cells. These age-related alterations in the properties of the two avian DNA polymerases may reflect structural or conformational changes in these enzymes.
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PMID:Altered nuclear deoxyribonucleic acid alpha-polymerases in senescent cultured chick embryo fibroblasts. 98 31

The antibiotic steffimycin B binds to double-stranded DNA as evidenced by difference spectroscopy and an increase of the thermal stability of DNA in the presence of the antibiotic. Salmon sperm DNA-steffimycin B complexes show a drastic decrease in template activity for Escherichia coli DNA polymerase I but not for DNA-idrected RNA polymerase. The differences in template properties of poly[d(A-T)] and poly (dG) - poly(dC)-antibiotic complexes,respectively, for DNA polymerase I and RNA polymerase suggest that the antibiotic interacts primarily with adenine or thymine bases or both in double-stranded DNA.
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PMID:Steffimycin B, a DNA binding agent. 109 Mar 4


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