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

Ca2+ plus Mg2+-dependent endodeoxyribonuclease was extracted from calf thymus chromatin and purified to a state free from contamination by other DNases. This DNase required both Ca2+ and Mg2+, or Mn2+ alone for its activity and the optimum pH for activity was at 6.5-7.5. No specificity for the 5'-base was observed. The molecular weight of the DNase was estimated to be about 25,000-30,000 by glycerol gradient centrifugation. Actin and antibody for pancreatic DNase (DNase I) did not inhibit the enzyme, whereas both strongly inhibited DNase I, suggesting that these two DNases are different enzymes.
...
PMID:Purification and characterization of the Ca2+ plus Mg2+-dependent endodeoxyribonuclease from calf thymus chromatin. 626 Jul 59

An apurinic endonuclease activity has been characterized in yeast mitochondrial. It is dependent on Mg2+, stimulated by about 50% in the presence of 50 mM NaCl and inhibited at higher NaCl concentrations. It is located in the inner mitochondrial membrane and requires high concentrations of detergent (1.5-3% Triton X-100) to be extracted. The same treatment extracts several other endonuclease activities: the two Mg2+-dependent endonuclease activities cleaving double-stranded DNA at pH 7.5 and 5.4 respectively, the ethidium-bromide-stimulated endonuclease activity, the endonuclease activity cleaving single-stranded DNA at pH 7.l5 [Jacquemin-Sablon et al. (1979) Biochemistry, 18, 119-127], and a manganese-stimulated deoxyribonuclease activity cleaving double-stranded DNA at pH 7.5 which has been discovered during the present work. Another endonuclease activity cleaving double-stranded DNA at pH 7.5 in the presence of Mg2+, slightly stimulated by low NaCl concentrations and inhibited by ethidium bromide is extracted from the membrane pellet remaining after the treatment with 1.5% Triton X-100 by a second treatment with 1.5% Triton X-100 plus 1 M KCl. The presence in the mitochondrial membrane of this apurinic endonuclease activity indicates that, like nuclear and prokaryotic DNA, yeast mitochondrial DNA is also subject to specialized repair systems.
...
PMID:Endonucleases in yeast mitochondria: apurinic and manganese-stimulated deoxyribonuclease activities in the inner mitochondrial membrane of Saccharomyces cerevisiae. 628 1

The various catalytic activities of the ATP-dependent deoxyribonuclease (DNase) of Bacillus laterosporus have pH optima at 6.3 and 8.3. Although the pH profile of ATP-dependent DNase activity on duplex DNA is bell shaped with a maximum at about pH 8.3, ATP-dependent DNAse activity on single-stranded DNA has optima at pH 6.3 and 8.3. ATPase activities dependent on double-stranded and single-stranded DNA have a high bell-shaped peak with a maximum at pH 6.3 with a low and broad shoulder at about pH 8.3. ATP-independent DNase activity also has optima at pH 6.3 and 8.3. The ratio of the amount of ATP hydrolyzed per number of cleaved phosphodiester bonds in DNA increases with decrease in the pH value of the reaction. The ratios obtained at pH 8.3 and 6.3 were respectively about 3 and 22 with duplex DNA as substrate and 5 and 17 with single-stranded DNA as substrate. Formation of a single-stranded region of 15000-20000 nucleotides, which is linked to duplex DNA and about half of which has 3'-hydroxyl termini, was observed at about pH 6.3, but not at above pH 7.5. Furthermore, the optimum concentrations of divalent cations for the activity producing the single-stranded region and the activity hydrolyzing ATP were identical (3 mM Mn2+ or 5 mM Mg2+). Thus the two activities are closely related. These results indicate that the enzyme has two different modes of action on duplex DNA which are modulated by the pH.
...
PMID:Two pH optima of adenosine 5'-triphosphate dependent deoxyribonuclease from Bacillus laterosporus. 628 73

Individual native nuclease activities from human leucocytes are separated by using two-dimensional gel electrophoresis in an apparatus that allows the simultaneous running of 28 gels. Proteins are separated by isoelectric focusing in a disc gel, followed by electrophoresis into a slab gel containing DNA. Protein denaturants are avoided in the second dimension by the use of a running pH well above the optimal pH for DNAase (deoxyribonuclease) activity. Electrophoresed gels are incubated in appropriate buffers to activate nuclease activity. After staining for intact DNA, the positions of active enzymes, unobscured by the presence of other proteins, are revealed as colourless spots in a reddish-purple field. The technique is easy to use and is sensitive to 50pg of DNAase I. Versatility is provided by the use of either acidic or basic electrophoresis running buffers and by the use of specific gel incubation conditions to reveal different sets of enzyme activities. Two DNAases active at pH 7.4 in the presence of Mg2+ and Ca2+, and sixteen DNAases active at acidic pH and not requiring metals, are detected. Treatment of the human enzymes with specific glycosidases reveals that many of the human DNAases are glycoproteins containing negatively charged moieties and may be derived from modification of parent activities.
...
PMID:Isoelectric focusing--polynucleotide/polyacrylamide-gel electrophoresis. A technique to separate and characterize nuclease activities. 674 32

A deoxyribonuclease has been purified 570-fold from the 14-day-old chick embryos. The purified enzyme requires Mg2+ or Mn2+ ions for maximum activity. The optimum pH is 9.0 in 20 mM Tris-HCl buffer. Its isoelectric point is 6.7. NaCl and N-ethylmaleimide strongly inhibit the reaction. An apparent molecular weight of 45,000 is determined by sedimentation in a glycerol density gradient. The enzyme hydrolyzes denatured DNA 50 to 100 times more rapidly than duplex DNA. RNA and synthetic polyribonucleotides are not substrate for the enzyme. DNase A catalyzes the endonucleolytic and exonucleolytic cleavages of single-stranded DNA. The enzyme produces DNA fragments having 70 to 100 nucleotides long at early time of reaction and then degrades these DNA fragments to acid-soluble materials, of which more than 70% is mononucleotides. In the exonucleolytic attack, the enzyme initiates hydrolysis of a single-stranded DNA from 5' to 3' direction. Chick embryo DNA-binding protein gives an intensive effect on the DNase A reaction by inhibiting the endonuclease activity rather than exonuclease activity under the standard assay conditions.
...
PMID:Deoxyribonuclease A of chick embryo. Partial purification and characterization of the enzyme. 682 17

The extract from rat liver chromatin contains two apurinic/apyrimidinic (AP) endodeoxyribonucleases named 0.2 M and 0.3 M isozymes according to the phosphate concentration necessary to elute them from an hydroxyapatite column. The 0.3 M isozyme is the main and perhaps the only chromatin AP endodeoxyribonuclease in the living cell. This 0.3 M isozyme was purified by successive chromatographies on hydroxyapatite, phosphocellulose, heparin-Sepharose and alkylated-depurinated DNA-cellulose. It has a molecular weight of approximately 39000; its optimum pH is around 8.0; it needs Mg2+ or Mn2+ to be active and the optimum concentration for Mg2+ is between 5 mM and 10 mM. The 0.3 M isozyme has no action on intact DNA strands or on alkylated sites; it cuts the phosphodiester bridge which is the immediate neighbour of the AP site on its 5' side leaving 3'-hydroxyl and 5'-phosphate ends. It has no associated exonuclease activity. To hydrolyze the phosphoester bond near the AP site, the enzyme makes a close contact with three base residues in the large groove of the DNA molecule.
...
PMID:The apurinic/apyrimidinic endodeoxyribonuclease of rat-liver chromatin. 682 67

Plasmid deoxyribonucleic acid (DNA) was tightly bound to cells of Escherichia coli at 0 degrees C in the presence of divalent cations. During incubation at 42 degrees C, 0.1 to 1% of this DNA became resistant to deoxyribonuclease. Deoxyribonuclease-resistant DNA binding and the ability to produce transformants became saturated when transformation mixtures contained 1 to 2 micrograms of plasmid NTP16 DNA and about 5 X 10(8) viable cells. Under optimum conditions, between 1 and 2 molecule equivalents of 3H-labeled NTP16 DNA per viable cell became deoxyribonuclease resistant. Despite this, only 0.1 to 1% of viable cells became transformed by saturating amounts of the plasmid. The results suggest that transport of DNA across the inner membrane is a limiting step in transformation. After transformation the bulk of labeled plasmid DNA remained associated with outer membranes. However, in vitro assays indicated that plasmid DNA would bind equally well to preparations of inner or outer membranes provided divalent cations were present to preparations of inner or outer membranes provided divalent cations were present. Divalent cations promoted differing levels of binding to isolated inner and outer membranes in the order Ca2+ much greater than Ba2+ greater than Sr2+ greater than Mg2+. This parallels their relative efficiencies in promoting transformation. Binding of plasmid DNA was greatly reduced when outer membranes were treated with trypsin; this suggests that protein components may be required for the binding or transport of DNA (or both) during transformation.
...
PMID:Transformation of Escherichia coli with plasmid deoxyribonucleic acid: calcium-induced binding of deoxyribonucleic acid to whole cells and to isolated membrane fractions. 700 49

Transformation experiments with Escherichia coli recipient cells and linear chromosomal deoxyribonucleic acid (DNA) are reported. E. coli can be rendered competent for DNA uptake by a temperature shock (0 degrees C leads to 42 degrees C leads to 0 degrees C) of the recipient cells in the presence of a high concentration of either Ca2+ or Mg2+ ions. Uptake of DNA into a deoxyribonuclease-resistant form, for which the presence of Ca2+ is essential, was possible during the temperature shock but appeared to occur most readily after the heat shock during incubation at 0 degrees C. When DNA was added to cells that had been heat shocked in the presence of divalent cations only, DNA uptake also occurred. This suggests that competence induction and uptake may be regarded as separate stages. Under conditions used to induce competence, we observed an extensive release of periplasmic enzymes, probably reflecting membrane damage induced during development of competence. After the conversion of donor DNA into a deoxyribonuclease-resistant form, transformants could be selected. It appeared that incubation, before plating, of the transformation mixture in a medium containing high Ca2+ and Mg2+ concentrations and supplemented with all growth requirements increased the transformation frequency. This incubation probably causes recovery of physiologically labile cells.
...
PMID:Transformation in Escherichia coli: stages in the process. 701 33

Cell-free extracts were prepared from either freshly grown or spray-dried cells of Micrococcus luteus ATCC 4698 by treatment with deoxyribonuclease and lysozyme. These extracts converted o-succinylbenzoic acid (OSB) to 1,4-dihydroxy-2-naphthoic acid (DHNA) as shown by spectrophotofluorometric and radioactivity assays. The conversion required the presence of ATP, CoA, and Mg2+. By use of [2-14C]OSB, the simultaneous production of the spirodilactone form of OSB was also demonstrated. The two products formed from OSB was also demonstrated. The two products formed from OSB were further characterized by gas chromatography combined with mass spectrometry. The production of the spirodilactone was suppressed by the addition of a preparation of the enzyme DHNA synthase obtained from Mycobacterium phlei. (This enzyme catalyzes the conversion of a CoA derivative of OSB to DHNA.) On mild acid treatment, the M. luteus extracts retained the ability to produce spirodilactone but lost the ability to form DHNA. These results are interpreted to mean that an OSB-CoA derivative is an intermediate in the conversion of OSB to DHNA by M. luteus and that two enzymes are involved, one to form the OSB-CoA derivative and the second to carry out a cyclization reaction.
...
PMID:Conversion of o-succinylbenzoate to dihydroxynaphthoate by extracts of Micrococcus luteus. 735 57

IL-2-dependent CTLL2 cells, upon IL-2 deprivation, die by apoptosis, which is accompanied by the fragmentation of genomic DNA. Two major deoxyribonuclease activities were detected in the extract of IL-2-deprived CTLL2 cells in a zymographic assay. They were designated nuc-58 and nuc-40, based on their apparent molecular mass of 58 and 40 kDa. The activity of both DNases was greatly induced in CTLL2 cells deprived of IL-2 or treated with the kinase inhibitor staurosporine. Deregulated expression of bcl-2 cDNA suppressed the induction of both nuclease activities. Nuc-58 was dependent on both Ca2+ and Mg2+ ions alone. Nuc-40 showed a preferential nuclear localization over that of nuc-58, which was found primarily in the cytoplasm. Optimal activity of both DNases required neutral pH and was inhibited by zinc ions. The physicochemical characteristics of the nucleases indicate that they are novel DNases associated with apoptosis in CTLL2 cells.
...
PMID:Deoxyribonuclease induction in apoptotic cytotoxic T lymphocytes. 776 59


<< Previous 1 2 3 4 5 6 7 Next >>

---