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)

Effects of VA-2, a component of quinoid antibiotic M-92, on the incorporation of radioisotope-labeled compounds into the cells of Staphylococcus aureus were studied. Deoxyribonucleic acid (DNA) synthesis was immediately inhibited by the addition of VA-2. Significant inhibitions of ribonucleic acid and protein syntheses and minor reduction of peptidoglycan synthesis were observed after a short delay. VA-2 immediately induced the degradation of DNA prelabelled with [14C]thymidine in the cells of S. aureus. In the examinations using E. coli enzyme and calf thymus DNA as a template, VA-2 prevented DNA-dependent DNA polymerase reaction. The inhibition of DNA polymerase I reaction was fairly reversed by increasing the concentration of template DNA, but slightly by that of the enzyme. Agarose gel electrophoresis showed that VA-2 elicited an extensive cleavage of PM2 cccDNA. VA-2 caused a primary conversion of the cccDNA to ocDNA at a low concentration (0.2 micrograms/ml), while at high concentrations (2.0 and 20 micrograms/ml) it cleaved the cccDNA to ocDNA and linear DNA progressively. These cleavages were observed even at 0 degrees C as well as at 37 degrees C, and were enhanced with the addition of a reducing agent such as 2-mercaptoethanol or sodium borohydride.
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PMID:Studies on a new antibiotic M-92 produced by micromonospora. V. Mechanism of action of the component VA-2. 685 68

A new deoxyribonucleic acid polymerase I mutant of Escherichia coli was isolated among conditional lethal mutants. Deoxyribonucleic acid replication in the mutant ceased in 20 min after the temperature was raised to 43 degrees C, and reinitiated when cells were further incubated at this temperature.
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PMID:Conditional-lethal deoxyribonucleic acid polymerase I mutant of Escherichia coli. 699 88

Deoxyribonucleic acid (DNA) polymerase delta has been purified 7800-fold from calf thymus, to a specific activity of 28 000 units/mg of protein. Similar to DNA polymerase delta from bone marrow [Byrnes, J.J., Downey, K. M., Black, V. L., & So, A. G. (1976) Biochemistry 15, 2817], the calf thymus enzyme is associated with 3'- to 5'-exonuclease activity. Both DNA polymerase and 3'- to 5'-exonuclease activities copurify on hydroxylapatite, DNA-cellulose, and molecular sieve chromatography. The ratio of exonuclease activity to polymerase activity is approximately 1:12. When the most highly purified fraction is subjected to polyacrylamide gel electrophoresis under nondenaturing conditions, both DNA polymerase and exonuclease activities have the same mobility at several acrylamide gel concentrations. Isoelectric focusing experiments have shown that both activities have the same pI. These data suggest that 3'- to 5'-exonuclease activity is an intrinsic property of DNA polymerase delta. The molecular weight of the enzyme, as estimated from measurements of Stokes radius and sedimentation coefficient, is 152 000.
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PMID:Purification of deoxyribonucleic acid polymerase delta from calf thymus: partial characterization of physical properties. 737 48

Deoxyribonucleic acid polymerase I was purified from Bacillus stearothermophilus to 50 to 70% homogeneity. Its molecular weight was 76,000. The enzyme was insensitive to sulfhydryl blocking agents and showed maximal activity at 60 degrees C, pH 8 to 9, 0.25 M KCl, and 0.02 M MgSO4. The rate of heat inactivation of the deoxyribonucleic acid polymerase followed first-order kinetics with a half-life of 90 min at 60 degrees C; the addition of 0.05% bovine serum albumin protected the enzyme, which could be heated for 180 min without loss of activity. The ratios of polymerase to nuclease activities were about 20 for 5'-3' exonuclease and more than 500 for 3'-5' exonuclease. The Km for deoxyribonucleoside-5'-triphosphates was 7 microM.
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PMID:Purification and properties of deoxyribonucleic acid polymerase from Bacillus stearothermophilus. 746 44

Microbial assessment of natural biodiversity is usually achieved through polymerase chain reaction (PCR) amplification. Deoxyribonucleic acid (DNA) sequences from natural samples are often difficult to amplify because of the presence of PCR inhibitors or to the low number of copies of specific sequences. In this study, we propose a non-specific preamplification procedure to overcome the presence of inhibitors and to increase the number of copies prior to carrying out standard amplification by PCR. The pre-PCR step is carried out through a multiple displacement amplification (MDA) technique using random hexamers as priming oligonucleotides and phi 29 DNA polymerase in an isothermal, whole-genome amplification reaction. Polymerase chain reaction amplification using specific priming oligonucleotides allows the selection of the sequences of interest after a preamplification reaction from complex environmental samples. The procedure (MDA-PCR) has been tested on a natural microbial community from a hypogean environment and laboratory assemblages of known bacterial species, in both cases targeting the small subunit ribosomal RNA gene sequences. Results from the natural community showed successful amplifications using the two steps protocol proposed in this study while standard, direct PCR amplification resulted in no amplification product. Amplifications from a laboratory assemblage by the two-step proposed protocol were successful at bacterial concentrations >or= 10-fold lower than standard PCR. Amplifications carried out in the presence of different concentrations of fulvic acids (a soil humic fraction) by the MDA-PCR protocol generated PCR products at concentrations of fulvic acids over 10-fold higher than standard PCR amplifications. The proposed procedure (MDA-PCR) opens the possibility of detecting sequences represented at very low copy numbers, to work with minute samples, as well as to reduce the negative effects on PCR amplifications of some inhibitory substances commonly found in environmental samples.
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PMID:Multiple displacement amplification as a pre-polymerase chain reaction (pre-PCR) to process difficult to amplify samples and low copy number sequences from natural environments. 1594 99


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