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:2.7.7.7 (DNA polymerase)
17,007 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

DNA polymerase was purified from a cloned isolate of Moloney murine leukemia virus (M-MuLV). Purified M-MuLV DNA polymerase, upon analysis by polyacrylamide gel electrophoresis, showed one major polypeptide of mol wt 80,000. Estimation of molecular weight from the sedimentation rate of the purifed enzyme in a glycerol gradient was consistent with a structure containing one polypeptide. M-MuLV DNA polymerase could transcribe ribopolymers, deoxyribopolymers, and heteropolymers as efficiently as did purified DNA polymerase from avian myeloblastosis virus (AMV). M-MuLV DNA polymerase, however, transcribed native 70S viral RNA less efficiently than did AMV DNA polymerase. Addition of oligo(dT) enhanced five to tenfold the transcription of 70S viral RNA by M-MuLV DNA polymerase. Purified enzyme also exhibited nuclease activity (RNase H) that selectively degraded the RNA moiety of the RNA-DNA hybrid. It did not degrade single-stranded RNA, single-stranded DNA, double-stranded RNA, and double-stranded DNA. M-MuLV DNA polymerase-associated RNase H acted as a random exonuclease. When [3-H]poly(A)-poly(dT) was used as a substrate, the size of the M-MuLV DNA polymerase-associated RHase H digested product was larger than the size of the digestion products by AMV DNA polymerase. The oligonucleotide digestion products could be further digested to 5'-AMP by snake venom phosphodiesterase, indicating that the products were terminated by 3'-OH groups. Alkaline hydrolysis of the oligonucleotide digestion products generated pAp, suggesting that M-MuLV DNA polymerase-associated RNase H cleaves at the 3' side of the 3',5'-phosphodiester bond. The ratios of the rates of DNA polymerase activity and RNase H activity were not significantly different in the murine and avian enzymes.
...
PMID:Studies on reverse transcriptase of RNA tumor viruses III. Properties of purified Moloney murine leukemia virus DNA polymerase and associated RNase H. 4 25

Rhodium(II) acetate, propionate, and butyrate showed a considerable variation in their antitumor activity against Ehrlich ascites tumor cells in mice, with the butyrate complex being the most active. The three complexes markedly inhibited DNA synthesis of Ehrlich ascites tumor cells in vivo. Rhodium (II) butyrate was the most potent inhibitor followed by the propionate complex. One hour after administration, rhodium(II) propionate and butyrate induce more uridine-5-3H incorporation into RNA than is seen in the controls. Equilibrium dialysis studied showed that rhodium(II) acetate-1-14C binds to single stranded DNA, poly-A, ribonuclease A, and bovine serum albumin but not to highly polymerized native calf thymus DNA, poly-G, or poly-C. In these cases binding occurred at the two axial positions of rhodium(II) acetate to a nitrogen donor in the ligands. The formation constants of the rhodium(II) acetate and propionate complexes with 5'-adenosine monophosphate were determined. The rhodium(II) propionate complex was more stable. Sedimentation and viscosity measurements of poly-A and poly-A/rhodium(II) acetate complexes indicate a high degree of intramolecular crosslinking in the rhodium(II) acetate/poly-A complex. The rhodium(II) carboxylate complexes were also found to be potent inhibitors of purified DNA polymerase I and RNA polymerase from Escherichia coli.
...
PMID:Interaction of Rhodium(II) carboxylates with molecules of biologic importance. 110 39

AMP and NaF each taken separately were shown to activate DNA polymerization catalyzed by Klenow fragment of DNA polymerase I by means of interaction of AMP or NaF with 3'----5'-exonuclease center of the enzyme. In the presence of NaF which is a selective inhibitor of 3'----5'-exonuclease center, AMP is an inhibitor of polymerization competitive with respect to dATP. Ki values and the pattern of inhibition with respect to dATP were determined for AMP, ADP, ATP, carboxymethylphosphonyl-5'-AMP, Pi, PPi, PPPi, methylenediphosphonic acid and its ethylated esters, phosphonoformic acid, phosphonoacetic acid and its ethylated esters as well as for some bicarbonic acids in the reactions of DNA polymerization catalyzed by Klenow fragment of DNA polymerase I (in the presence of NaF) and DNA polymerase alpha from human placenta in the presence of poly(dT) template and r(pA)10 primer. All nucleotides and their analogs were found to be capable of competing with dATP for the active center of the enzyme. Most of the analogs of PPi and phosphonoacetic acid are inhibitors of Klenow fragment competitive with respect to dATP. Nowever these analogs display a mixed-type inhibition in the case of human DNA polymerase alpha. We postulated a similar mechanism of interaction for dNTP with both DNA-polymerases. It is suggested that each phosphate group of PPi makes equal contribution to the interaction with DNA polymerases and that the distance between the phosphate groups is important for this interaction. beta-phosphate of NTP or dNTP is suggested to make negligible contribution to the efficiency of the formation of enzyme complexes with dNTP. beta-phosphate is likely to be an essential point of PPi interaction with the active center of proteins during the cleavage of the alpha-beta-phosphodiester bond of dNTP in the reaction of DNA polymerization.
...
PMID:[Interaction of dNTP-binding sites of human DNA polymerase alpha and The Klenow fragment of Escherichia coli DNA polymerase I with nucleotides, pyrophosphate and their analogs]. 216 89

The DNA-dependent RNA polymerase of vaccinia virus contains 8 to 10 virus-encoded polypeptides. We have mapped the gene encoding an 18-kilodalton RNA polymerase subunit to D7R, the seventh open reading frame of the HindIII D genomic subfragment. Localization of this gene was achieved by using antibody to the purified RNA polymerase for immunoprecipitation of the in vitro translation products of in vivo-synthesized early mRNA selected by hybridization to cloned DNA fragments. The identification was confirmed by translation of D7R transcripts made in vitro with bacteriophage T7 RNA polymerase. The phenotypes of two previously isolated conditionally lethal temperature-sensitive mutants that map to D7R (J. Seto, L. M. Celenza, R. C. Condit, and E. G. Niles, Virology 160:110-119, 1987) are consistent with an essential role of this subunit in late transcription. This polymerase gene, designated rpo18, predicts a polypeptide of 161 amino acids with a molecular mass of 17,892. The rpo18 gene is transcribed early in infection, even though the 5'-TAAATG-3' motif, which is conserved among many genes of the late class, is present near the RNA start site. Characterization of the 5' end of the early transcript by several different methods, including cDNA cloning, revealed a poly(A) leader with up to 14 adenylate residues, whereas only 3 are present in the corresponding location of the DNA template. Similar but somewhat longer poly(A) leaders have previously been observed in mRNAs of late genes. We noted a TAAATG motif near the initiation site of several other early genes, including the viral DNA polymerase, and carried out additional experiments to demonstrate that their early transcripts also have 5' poly(A) leaders. Thus, formation of the poly(A) leader is not exclusively a late function but apparently depends on sequences around the transcription initiation site.
...
PMID:Identification of the vaccinia virus gene encoding an 18-kilodalton subunit of RNA polymerase and demonstration of a 5' poly(A) leader on its early transcript. 233 25

Ten patients with chronic type B hepatitis were treated with three courses of adenine arabinoside monosphosphate (Ara-AMP). The drug was given intramuscularly at a dosage of 10 mg/kg/day in ten-day courses during each of three sequential months. The patients were all men, aged 31-61 years, who were known to have had chronic hepatitis for one to four years. Each of the ten-day courses of Ara-AMP was accompanied by a marked inhibition in the serum levels of hepatitis B virus (HBV) DNA and DNA polymerase activity. However, HBV-DNA remained detectable in every patient during treatment and invariably rebounded to pretreatment levels soon after each course was stopped. One patient developed severe, and two patients developed mild neuromuscular side effects. During a 12-18-month follow-up period, only one of the ten patients has had a sustained clinical, serum biochemical, and serological remission. In this patient, serum HBeAg, HBV-DNA, and DNA polymerase became undetectable three months after the final course of treatment; serum aminotransferase levels subsequently fell into the normal range; and a follow-up liver biopsy showed a diminution in the chronic inflammatory cell activity and a disappearance of intrahepatic hepatitis B core antigen reactivity. Thus, multiple ten-day courses of Ara-AMP do not induce a high rate of remissions in this disease and are associated with appreciable neuromuscular toxicity. Ara-AMP is a potent inhibitor of serum levels of hepatitis B virus, but Ara-AMP therapy has not been shown to have long-term beneficial effects in chronic type B hepatitis.
...
PMID:Treatment of chronic type B hepatitis with multiple ten-day courses of adenine arabinoside monophosphate. 257 92

Since interferon inducible 2',5'-oligoadenylate (2,5An) synthetase activity is present in a wide variety of cells and is affected by various hormonal conditions, primary human mammary tumor extracts were examined for the constitutive presence of this enzyme and its possible relationship with the various hormonal receptor levels in these tissues. Further, since 2,5An synthetase has been implicated as a possible factor controlling cell replication, we assayed DNA polymerases in these same tumor extracts to determine any correlation between 2,5An synthetase activity and growth potential. A survey of the soluble extracts from 24 different surgically removed human mammary tumor specimens for 2,5An synthetase activity indicated that this enzyme was indeed present in all extracts but in widely varying amounts of activity (31-2,666 nmol adenosine 5'-phosphate incorporated/mg protein). The 2,5An synthesized in the enzymic reactions ranged in size from di- to hexamers, with trimers being the abundant 2,5An in the majority of tumors. A comparison of the assay results for estrogen and progestin receptors with 2,5An synthesis indicated that high 2,5An synthetase activity was found in both estrogen or progestin positive and negative tumors. Thus, 2,5An synthetase activity was unrelated (r = 0.329 and 0.077, respectively, for estrogen and progestin receptors) to the hormonal receptor content of these tumors. A similar comparison was made between 2,5An synthesis and assay results for the activities of DNA polymerase alpha, regarded as the principal DNA replicating enzyme, and DNA polymerase beta, regarded as the DNA repair enzyme. Although the activity of the polymerases were also quite varied, the majority of tumor extracts demonstrated higher alpha polymerase activity with no parallel difference between the alpha and beta enzymes. There was, however, a weak correlation (r = 0.751) between 2,5An synthetase activity and DNA polymerase alpha activity among the tumors examined. Less of a correlation existed with DNA polymerase beta activity (r = 0.600). These results suggested that the potential of the tumors to synthesize 2,5An was unrelated to their hormonal responsiveness and only weakly related to their growth potential reflected by DNA polymerase alpha activity.
...
PMID:2',5'-oligoadenylate synthetase activity in human mammary tumors and its potential correlation with tumor growth or hormonal responsiveness. 377 41

Mitogen-stimulated scheduled DNA synthesis and DNA excision repair in human lymphocytes, as well as DNA polymerase a activity in a cell-free system, were inhibited by an electrophilic metabolite of benzo[a]pyrene. This metabolite, (+/-)-anti-(7r,8t)-dihydroxy-(9,10t)-epoxy-7,8,9,10-tetrahyd robenzo[a]pyrene (BPDE), covalently binds to cellular macromolecules and is mutagenic, carcinogenic, and cytotoxic. Human lymphocytes treated with BPDE at concentrations greater than 500-800 ng/ml showed decreases in both mitogen-stimulated DNA synthesis and excision repair of damaged DNA but did not exhibit overt cytotoxicity (excluded trypan blue and maintained an adenylate charge of greater than 0.7). Formation of, and total concentration of, BPDE-DNA adducts was not correlated with inhibition of DNA synthesis. DNA polymerase alpha studies using a cell-free system showed that enzymatic activity was not diminished when purified polymerase was treated with BPDE prior to the addition of template DNA. When the template DNA concentration was varied, BPDE inhibition of enzyme activity was uncompetitive. BPDE inhibition of enzyme activity was found to be noncompetitive when concentrations of dATP, dCTP, or dTTP were varied and competitive when the concentration of dGTP was varied. The data indicate that BPDE competitively inhibits interaction of dGTP with the template-DNA polymerase alpha complex.
...
PMID:Inhibition of DNA synthesis by an electrophilic metabolite of benzo[a]pyrene. 608 90

The distribution in human tissues has been determined of the new DNA polymerase activity designated DNA polymerase Cm, first isolated from the human melanoma cell line A-375. Tissue samples were fractionated by ion exchange chromatography on diethylaminoethyl cellulose and phosphocellulose and by affinity chromatography on poly(2'-O-methylcytidylate)-Sepharose. DNA polymerase activity was monitored with poly(2'-O-methylcytidylate) . oligodeoxyguanylate and poly(adenylate) . oligodeoxyribothymidylate, the most specific and most sensitive template primers, respectively, for DNA polymerase Cm. Tissues were scored as to presence or absence of detectable DNA polymerase Cm activity as well as to their validity for scoring dependent on content of total DNA polymerase activity. On this basis, seven of 14 malignant and none of 11 normal or embryonic tissues were found to contain detectable levels of DNA polymerase Cm.
...
PMID:Distribution of DNA polymerase Cm in normal and malignant human tissues. 615 70

The use of 5'-AMP as a ligand for the affinity chromatography of DNA polymerases with intrinsic 3' to 5' exonuclease activities was investigated. The basis for this is that 5'-AMP would be expected to act as a ligand for the associated 3' to 5' exonuclease. The requirements for binding of Escherichia coli DNA polymerase I, T4 DNA polymerase, and calf thymus DNA polymerase delta, all of which have associated 3' to 5' exonuclease activities, to several commercially available 5'-AMP supports with different linkages of 5'-AMP to either agarose or cellulose were examined. The DNA polymerases which possessed 3' to 5' exonuclease activities were bound to agarose types in which the 5'-phosphoryl group and the 3'-hydroxyl group of the AMP were unsubstituted. Bound enzyme could be eluted by either an increase in ionic strength or competitive binding of nucleoside 5'-monophosphates. Magnesium was found to reinforce the binding of the enzyme to these affinity supports. DNA polymerase alpha, which does not have an associated 3' to 5' exonuclease activity, did not bind to any of these columns. These differences can be used to advantage for the purification of DNA polymerases that have associated 3' to 5' exonuclease activities, as well as a means for establishing the association of 3' to 5' exonuclease activities with DNA polymerases.
...
PMID:Selective affinity chromatography of DNA polymerases with associated 3' to 5' exonuclease activities. 637 60

Preparations of DNA polymerase alpha from early embryos of Drosophila melanogaster catalyze the ATP-dependent synthesis of DNA with single-stranded M13 DNA or poly(dT) templates. In the case of M13 DNA, GTP, but not UTP or CTP, can replace ATP. The reaction is completely dependent on added template and is not inhibited by alpha-amanitin. Alkaline hydrolysis of the product synthesized in the presence of [alpha-32P]dATP and poly(dT) generates 32P-labeled 3'(2') adenylate, showing that a covalent ribo-deoxynucleotide linkage is formed. Furthermore, incorporation of ribonucleotides occurs at the 5' end of the newly synthesized polynucleotide chain. These findings are consistent with the hypothesis that a ribo-oligonucleotide primer is synthesized by primase action and subsequently elongated by DNA polymerase. Under the appropriate conditions, DNA polymerase I from Escherichia coli can elongate primers formed by primase in the presence of ATP and poly(dT). Primase activity copurifies with DNA polymerase alpha and may be part of the multisubunit polymerase molecule.
...
PMID:A DNA primase activity associated with DNA polymerase alpha from Drosophila melanogaster embryos. 680 12


1 2 3 Next >>

---