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:3.1.25.1 (deoxyribonuclease)
1,471 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of various metabolic inhibitors (carbonylcyanid-m-chlorophenylhydrazone, nigericin, valinomycin, dicyclocarbodiimide, arsenate, NaF, etc.) and lipid-soluble synthetic ions (tetraphenylphosphonium bromide and tetraphenylboron sodium) on deoxyribonucleic acid (DNA) entry during transformation of Ca2+-treated Escherichia coli cells with plasmid DNA and on cell viability was investigated. In contrast to intact cells, Ca2+-treated E. coli cells were permeable to nigericin, valinomycin, and the other drugs tested. The inhibitors differentially affected [14C]proline active transport, and whereas some drugs inhibited transformation, the effects did not correlate with the effects on transport. The most potent inhibitors of transformation were nigericin, dicyclocarbodiimide, and tetraphenylboron sodium. Carbonylcyanid-m-chlorophenylhydrazone, tetraphenylphosphonium bromide, and valinomycin were relatively inactive. Tetraphenylboron sodium- and nigericin-treated cells bound were plasmid [14C]DNA in the deoxyribonuclease-resistant form than the control and other sample cells. Nevertheless, te penetration of exogenous plasmid DNA into the cell was greatly reduced, at least in case of nigericin. Unlike the other drugs, nigericin and dicyclocarbodiimide drastically affected the cell viability, the former within very short times of interaction. It is concluded that proton motive force does not play any significant role in DNA entry into Ca2+-treated E. coli cells. The results also suggest that adenosine 5'-triphosphate is not required for DNA entry either. The inhibitory effect of certain drugs is discussed in terms of structural perturbations induced by the drugs in cell envelope membranes.
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PMID:Effect of metabolic inhibitors on entry of exogenous deoxyribonucleic acid into Ca2+-treated Escherichia coli cells. 701 27

Spirosomes, very find spiral particles, were isolated from a protoplastlysate of Lactobacillus brevis ATCC 8287 by differential centrifugation and purified further by potassium tartrate density gradient centrifugation. The purified spirosome preparation showed a maximum peak around 275 nm on the ultraviolet absorption spectrum and it consisted of about 94.5% protein. The buoyant density in CsCl of the spirosomes was 1.320 g/cm3. The spirosomes were composed mainly of a single protein (spirosin with an apparent molecular weight of about 95,000 as determined by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis. The protein of the spirosomes was found to be composed predominantly of neutral amino acids accompanied by approximately equal amounts of acidic and basic amino acids. The spirosomes showed one antigenic determinant in the immunodiffusion test. The spirosomes were readily degraded by the action or proteolytic enzymes and lost their antigenicity, but they were not affected by treatment with either deoxyribonuclease or ribonuclease. The spiral structure of the spirosome was also found to be disintegrated by treatment with 1 M guanidine hydrochloride, 4 M urea or 0.1% SDS, but not by the action of deoxycholate, nonionic detergents or mercaptoethanol, as observed in the electron microscope.
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PMID:Purification and characterization of spirosomes in Lactobacillus brevis. 710 79

A hemolysin produced by Treponema hyodysenteriae, the etiological agent of swine dysentery, was investigated. A virulent isolate (B204) was inoculated into a standard culture medium consisting of Trypticase soy broth without dextrose (BBL Microbiology Systems) supplemented with 10% fetal calf serum in an atmosphere of 70:30 deoxygenated H2-CO2. Sterile cell-free filtrates were prepared at 2-h intervals and assayed for hemolytic activity by using washed sheep erythrocytes. The maximum hemolytic titer was obtained during the early log phase of growth (4 h). A loss of hemolytic activity was observed when cell-free filtrates were stored at 23 and 4 degrees C. Storage at -20 or -80 degrees C after lyophilization resulted in retention of the hemolytic titer for periods of up to 30 days. Enzymatic inactivation of the hemolysin was accomplished with pronase, but not with deoxyribonuclease, ribonuclease, lipase, or trypsin. Addition of exogenous ribonucleic acid-core to the standard culture medium resulted in a dose-dependent increase in the amount of hemolysin produced. The hemolysin could be purified by acid and ammonium sulfate precipitation followed by ion exchange and molecular sieve chromatography. The molecular weight of the hemolysin was 68,000 when determined by sodium dodecyl sulfate-polyacrylamide slab gel electrophoresis.
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PMID:Investigation of a hemolysin produced by enteropathogenic Treponema hyodysenteriae. 721 45

A folate-binding protein (binder) from human choroid plexus was solubilized with Triton X-100 and partially purified in three steps: (1) affinity chromatography, (2) Sephadex G-200 column chromatography, and (3) polyacrylamide gel electrophoresis. When the partially purified binder was subjected to sodium dodecyl sulfate--polyacrylamide gel electrophoresis, the binding activity was located in the region of the gel with a molecular weight between 45,000 and 60,000. The specific activity of the binder after the three purification steps was 1.2 mu g folic acid/mg protein, a 316-fold purification. Binding activity of the partially purified binder decreased below pH 6.0 and above pH 8.0, was unaffected by treatment with ribonuclease or deoxyribonuclease, but was abolished with trypsin, chymotrypsin, or protease (Streptomyces griesus). The binding of folic acid to the human binder was inhibited by folate Greater Than H4-folate Greater Than methyl-H4-folate approximately dihydrofolate approximately pteroic acid Greater Than methotrexate approximately aminopterin.
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PMID:Partial purification and characterization of a folate-binding protein from human choroid plexus. 727 9

An ATP-dependent deoxyribonuclease was isolated from lymphocyte nuclei. The enzyme preparation sediments with about 4 S through sucrose gradients and shows one stainable band after sodium dodecyl sulfate gel electrophoresis. We find three, possibly four, activities associated with the enzyme: a DNA-independent ATPase activity; an ATP-independent endonuclease; an ATP-dependent nuclease which degrades nicked DNA to acid-soluble material; and an unwinding activity producing single-stranded regions in nicked DNA.
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PMID:A lymphocyte ATP-dependent deoxyribonuclease. Isolation and properties. 730 58

Cystic fibrosis (CF), a lethal disease common to Caucasians, is characterized by a defect in the CF transmembrane conductance regulator and the resulting defective cAMP-regulated Cl- secretion by epithelial cells. Clinical manifestations include both pancreatic and pulmonary insufficiency. Traditional therapeutic modalities address these problems with pancreatic enzyme replacement, vitamins and nutritional supplementation, antibiotics, and respiratory therapy. However, newer therapies directed at the specific underlying defects have emerged. In this review, we discuss agents that increase Cl- secretion via preserved Cl- secretory pathways, such as uridine triphosphate, or that enhance Na+ resorption, such as amiloride, thereby correcting altered airway secretions. We also discuss agents, including deoxyribonuclease (DNase), that directly reduce sputum viscosity. CF is an early target for in vivo gene therapy, since it is a monogenic autosomal recessive disease in which restoration of normal cAMP-regulated Cl- conductance can be achieved by complementation with a normal gene. The early clinical gene therapy therapy work, with gene introduction by both viral and nonviral vectors, is discussed.
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PMID:Molecular strategies for therapy of cystic fibrosis. 759 94

Patients in the intensive care unit (ICU) with compromised lung function often have excessive pulmonary secretions and have difficulty clearing mucus. A variety of pharmacotherapeutics have been used in an attempt to change the rate, amount, and viscosity of respiratory secretions. These drugs are known as mucokinetic or mucolytic drugs, but their efficacy remains controversial in the research literature. Most commonly used methods of mucolysis/mucokinesis include: bland aerosols (saline), pH adjustment (sodium bicarbonate), and disulfide disruption (N-acetylcysteine, MUCOMYST). Clinical research needs to be done on the use of recombinant human deoxyribonuclease (rhDNase) in ICU patients because recombinant human deoxyribonuclease affects only purulent secretions, which makes it a safe, easily tolerated compound. Nursing interventions in the control of mucus in the ICU patient needs to be re-examined in light of recent research where the efficacy of chest percussion was questioned, as was the use of saline bolus instillation before suctioning and the potential for dornase alfa.
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PMID:Mucolytics and the critically ill patient: help or hindrance? 774 33

Our recent structure-activity analysis of Fpg protein of Escherichia coli, using oligodeoxynucleotides containing various 8-oxopurine derivatives, has allowed us to postulate an enzyme mechanism involving protonation of 8-oxoguanine at O-6 and nucleophilic attack of the deoxyribose moiety at C-1' leading to the formation of an enzyme-substrate Schiff base intermediate (Tchou, J., Bodepudi, V., Shibutani, S., Antoshechkin, I., Miller, J., Grollman, A. P., and Johnson, F. (1994) J. Biol. Chem. 269, 15318-15324). In this paper, sodium cyanoborohydride has been used to convert the transient intermediate to a covalent enzyme-DNA complex. The location of the active site of Fpg protein is further delineated using two approaches. 1) A radiolabeled DNA substrate is used to tag the active site of Fpg protein, using sodium cyanoborohydride. The active site is mapped to the first 73 amino acid residue fragment by cyanogen bromide cleavage analysis. 2) A maltose-binding protein fusion system is used to generate amino-terminal modifications of Fpg protein to explore the role of the amino-terminal region in DNA binding and catalysis. Results support the conclusion that the active site of Fpg protein is located at or near the amino terminus. Thus, Fpg protein may act in a similar fashion as T4 endonuclease V, a DNA repair enzyme that uses its amino-terminal alpha-amino group of threonine to carry out catalysis via Schiff base formation (Dodson et al., 1993).
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PMID:The catalytic mechanism of Fpg protein. Evidence for a Schiff base intermediate and amino terminus localization of the catalytic site. 774 6

The glycosylase/abasic lyase T4 endonuclease V initiates the repair of ultraviolet light-induced pyrimidine dimers. This enzyme forms an imino intermediate between its N-terminal alpha-NH2 group and C-1' of the 5'-residue within the dimer. Sodium borohydride was used to covalently trap endonuclease V to a 49-base pair oligodeoxynucleotide containing a site-specific cyclobutane thymine dimer. The bound and free oligonucleotides were then subjected to nuclease protection assays using DNase I and a complex of 1,10-phenanthroline-copper. There was a large region of protection from both nucleases produced by endonuclease V evident on the strand opposite and asymmetrically opposed to the dimer. Little protection was seen on the dimer-containing strand. The existence of a footprint with the 1,10-phenanthroline-copper cleavage agent indicated that endonuclease V was interacting with the DNA predominantly via the minor groove. Methylation by dimethyl sulfate yielded no areas of protection when endonuclease V was covalently attached to the DNA, indicating that the protein may closely approach the DNA without direct contact with the bases near the thymine dimer. The Escherichia coli proteins Fpg and photolyase display a very different pattern of nuclease protection on their respective substrates, implying that endonuclease V recognizes pyrimidine dimers by a novel mechanism.
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PMID:T4 endonuclease V protects the DNA strand opposite a thymine dimer from cleavage by the footprinting reagents DNase I and 1,10-phenanthroline-copper. 787 17

Deoxyribonuclease activity was detected in E. granulosus protoscoleces from sheep hydatid cysts by electrophoresis in agarose gels of DNA fragments obtained after incubation of integral DNA with a protoscoleces preparation. Preliminary characterization showed that deoxyribonuclease activity was optimal at neutral-alkaline pH, magnesium ions were required, and it was able to digest different types of DNA, making random cuts. Electrophoresis in DNA-containing sodium dodecylsulfate (SDS)-polyacrylamide gels indicated a relative molecular mass, under non-reducing conditions, of 32 kDa. Deoxyribonuclease activity was also found in sheep hydatid fluid. It shared optimal pH, ionic and substrate requirements with the enzyme from protoscoleces but had a higher relative molecular mass (40 kDa), the same as that of normal sheep serum deoxyribonuclease.
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PMID:Deoxyribonuclease activity in Echinococcus granulosus protoscoleces and hydatid fluid. 808 90


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