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)

We have purified the DNA polymerase from Mycoplasma orale to homogeneity. The protein structure of the enzyme was declined by sodium dodecyl sulfate gel electrophoresis, which revealed a single band of 116 000 daltons that was coincident with the polymerase activity profile in the final step of DNA--cellulose chromatography, and by two-dimensional gel analysis, which demonstrated a single protein species at pI = 6.8 that was congruent with enzyme activity and contained the same 116 000 polypeptide. although severe enzyme aggregation occurs during nondenaturing gel electrophoresis, a monomer species can be resolved with a Mr of 140 000 by the Ferguson plot analysis. Gel filtration and velocity gradient centrifugation yield a Stokes radius of 4.8 nm and a sedimentation coefficient of 5.6 S, respectively, from which Mr values of 106 000--128 000 can be computed. The different size values suggest that the polymerase molecule is asymmetric. The purified enzyme has a specific activity of approximately 6 x 10(5) units/mg of protein and in completely devoid of exodeoxyribonuclease and endodeoxyribonuclease activities, at exclusion limits of 10(-4)--10(-6%) of the polymerase activity. The mechanism of polymerization is moderately processive, with an average of 14 +/- 4 nucleotides incorporated per binding event, and the "effective template length" on activated DNA is approximately 40 nucleotides.
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PMID:Structural and enzymological characterization of the homogeneous deoxyribonucleic acid polymerase from Mycoplasma orale. 49 65

A deoxyribonuclease activity has been identified in the nuclei of the human cervical carcinoma HeLa. This activity has the novel property of existing as a single strand specific endo- and exodeoxyribonuclease activity. These activities are ionic strength sensitive, with retardation of activity occurring at 50 mM NaCl and above, with the Mn++ ion preferred over the Mg++ ion as activating cation. This activity extensively damages DNA via its single strand nicking and gaping activity. The method used to solubilize this activity as well as the enzyme's characteristics are discussed.
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PMID:Identification of a deoxyribonuclease activity in the nuclei of the cervical carcinoma HeLa. 301 42

Apurinic and/or apyrimidinic (AP) sites were excised from PM2 phage DNA by two enzymes: an AP endodeoxyribonuclease isolated from rat neocortex chromatin and a rat brain exodeoxyribonuclease, DNase B III. The resulting gap was filled with DNA polymerase beta prepared from rat liver and finally ligated by Escherichia coli DNA ligase.
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PMID:Excision of apurinic and/or apyrimidinic sites from DNA by nucleolytical enzymes from rat brain. 327 4

DNA from T7 phage containing AP (apurinic/apyrimidinic) sites was repaired by the successive actions of three chromatin enzymes [AP endodeoxyribonuclease, DNAase IV (5'----3'-exodeoxyribonuclease) and DNA polymerase-beta] prepared from rat liver and T4-phage DNA ligase. Since DNA ligase is also found in rat liver chromatin, all the activities used for the successful repair in vitro are thus present in the chromatin of a eukaryotic cell. Our results show, in particular, that the chromatin DNAase IV is capable of excising the AP site from the DNA strand nicked by the chromatin AP endodeoxyribonuclease. We did not try to combine all the enzymes, since competition between some of them might have prevented the repair; we have, for instance, shown that DNA ligase can seal the incision 5' to the AP site made by the AP endodeoxyribonuclease. Changes in chromatin structure during repair might perhaps prevent this competition when nuclear DNA is repaired in the living cell.
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PMID:Repair of depurinated DNA with enzymes from rat liver chromatin. 674 58

Streptomyces coelicolor A3(2) produces several intra and extracellular enzymes with deoxyribonuclease activities. The examined N-terminal amino acid sequence of one of extracellular DNAases (TVTSVNVNGLL) and database search on S. coelicolor genome showed a significant homology to the putative secreted exodeoxyribonuclease. The corresponding gene (exoSc) was amplified, cloned, expressed in Escherichia coli, purified to homogeneity and characterized. Exonuclease recExoSc degraded chromosomal, linear dsDNA with 3'-overhang ends, linear ssDNA and did not digest linear dsDNA with blunt ends, supercoiled plasmid ds nor ssDNA. The substrate specificity of recExoSc was in the order of dsDNA>ssDNA>3'-dAMP. The purified recExoSc was not a metalloprotein and exhibited neither phosphodiesterase nor RNase activity. It acted as 3'-phosphomonoesterase only at 3'-dAMP as a substrate. The optimal temperature for its activity was 57 degrees C in Tris-HCl buffer at optimal pH=7.5 for either ssDNA or dsDNA substrates. It required a divalent cation (Mg(2+), Co(2+), Ca(2+)) and its activity was strongly inhibited in the presence of Zn(2+), Hg(2+), chelating agents or iodoacetate.
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PMID:An exodeoxyribonuclease from Streptomyces coelicolor: expression, purification and biochemical characterization. 1722 25