Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.25.1 (deoxyribonuclease)
 1,471 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The present investigation was undertaken to determine the types and extent of DNA damage resulting from incubation of primary cultures of bovine lens epithelial cells with hydrogen peroxide. Significant numbers of DNA single-strand breaks were detected by alkaline elution after exposure to as little as 25 microM H2O2 for 5 min at 37 degrees C. The extent of single-strand breakage was concentration dependent and linear from 25 to 200 microM H2O2. The observed single-strand breaks appear primarily due to the action of the hydroxyl radical via a Fenton reaction as both an iron chelator, 1,10-phenanthroline and OH. scavengers, including DMSO, KI and glycerol, significantly inhibited the DNA-damaging effect of H2O2. Diethyldithiocarbamate, an inhibitor of superoxide dismutase, further potentiated the DNA-damaging effects of H2O2, presumably by increasing the steady-state concentration of Fe2+. DNA-protein cross-linking was not observed. In addition, significant levels of 5,6-saturated thymine residues or pyrimidine dimers were not detected after modification of the alkaline elution methodology to allow the use of either E. coli endonuclease III or bacteriophage T4 endonuclease V, respectively. No double-strand breaks were detected after incubation of epithelial cell cultures with H2O2 concentrations of up to 400 microM for 10 min and subsequent neutral filter elution. Since, in vivo, the lens epithelium contains populations of both quiescent and dividing cells, the degree of susceptibility to oxidative damage was also studied in actively growing and plateau-phase cultures. Reduced levels of single-strand breakage were observed when plateau-phase cultures were compared to actively growing cells. In contrast, essentially no differences in repair rates were noted at equitoxic doses of H2O2. The above results suggest that lens epithelial cells may be particularly sensitive to oxidative damage and thus are a good model system in which to study the effects of oxidative stress.
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PMID:Hydrogen peroxide-induced DNA damage in bovine lens epithelial cells. 215 69

Deoxyribonucleic acid (DNA) extracted from canine venereal tumours was capable of changing normal cells to morphologically abnormal cells in an in vitro system of L-fibroblasts. The observed effects were proportional to the concentration of the nucleic acid extract used; the higher the concentration, the more pronounced the effect. Inactivation of this effect by deoxyribonuclease indicated that the active nucleic acid moiety was DNA. Purified RNA did not appear to contribute to the observed activity. The activity was enhanced by diethyl-amino ethyl-dextran (DEAE-D) and dimethyl sulphoxide (DMSO) and the data showed that 20% DMSO was superior to 300 g/ml DEAE-D as an enhancing agent.
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PMID:Enhancement of the biological activities of deoxyribonucleic acid extracted from canine venereal tumours. 628 55

In 1995, we discovered new antiherpetic antibiotics, called fattiviracins. The producing organism was classified as a strain belonging to Streptomyces microflavus. The strain produced at least 13 fattiviracin derivatives (FV-1 to FV-13). Fattiviracins were obtained as a white amorphous powder, and their molecular weights are in the range of 1400 to 1500. They are readily soluble in water, methanol, pyridine, and DMSO, but insoluble in other organic solvents. Fattiviracins have macrocyclic diesters formed by the binding of two trihydroxy fatty acids and two D-glucose residues in the molecule, and they can be divided into five families according to the length of the fatty acid moiety. Fattiviracins have potent activity against enveloped DNA viruses such as the herpes family, HSV-1, and VZV and enveloped RNA viruses such as influenza A and B viruses, and three strains of HIV-1, with EC(50) values on the order of a few micrograms per milliliter. The biosynthetic pathway of fattiviracins is also becoming clearer. Using bacitracin-resistant strains, enhanced and astringent production of fattiviracin was achieved. Fattiviracin FV-13, which has the longest fatty acid chains in the molecule, was dramatically enhanced by a C(55)-isoprenyl phosphate metabolism. In addition, we have screened various inhibitors of enzymes such as alkaline protease, glucosyltransferase, glucuronidase, phospholipase, deoxyribonuclease, DNA methyltransferase, and DNA topoisomerase. All the inhibitors we discovered are briefly summarized in this paper.
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PMID:[Metabolites produced by actinomycetes--antiviral antibiotics and enzyme inhibitors]. 1529 17