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)

A deoxyribonuclease inhibitor has been purified from KB cells by chromatography on single-stranded DNA-cellulose. Polyacrylamide gel electrophoresis showed the purified preparation to contain two major polypeptides in sodium dodecyl sulfate, with molecular weights of 72,000 and 65,000, but only one major band (with a molecular weight of approximately 140,000) after electrophoresis under nondenaturing conditions. The protein inhibits the hydrolysis of single-stranded DNA by KB DNase, DNase I, DNase II, and nuclease S1, but has no effect on the hydrolysis of double-stranded DNA by these enzymes. The inhibitor causes a reduction in the rate of hydrolysis of DNA by the deoxyribonuclease, probably by reducing the effective concentration of substrate.
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PMID:A deoxyribonucleic acid binding protein from KB cells which inhibits deoxyribonuclease activity on single-stranded DNA. 42 57

We have characterized a deoxyribonuclease from Streptomyces glaucescens that cleaves double-stranded DNA preferably between the dinucleotide 5'-CC-3'. The cleavage specificity was demonstrated by both analysis of the terminal nucleotides of the generated fragments and DNA sequencing of partially digested DNA. Digestion of lambda DNA with this enzyme resulted in the production of double-stranded fragments with 5' and/or 3'-protruding single-stranded tails. DNase I footprinting experiments indicated that the nuclease specifically binds to its cleavage sites on the DNA under non-catalytic conditions. The enzyme is not affected by cytosine methylation in hemimethylated DNA.
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PMID:A Streptomyces glaucescens endodeoxyribonuclease which shows a strong preference for CC dinucleotide. 153 67

To clarify the relationship between changes in serum pancreatic enzymes and pathological changes in pancreatic parenchyma, this study was performed by using rat models with acute pancreatitis. The models were rats with edematous and necrotizing pancreatitis. Amylase, lipase, ribonuclease (RNase), and deoxyribonuclease (DNase I, II) in the serum were determined for 48 h after the development of pancreatitis. Amylase and lipase levels rose directly in both pancreatitis groups. These enzymes in the necrotizing pancreatitis group were higher than those in the edematous pancreatitis group, but there was no significant difference. RNase levels also rose markedly, but there was no obvious difference between either of the pancreatitis groups. On the other hand, DNase levels were high in the necrotizing pancreatitis group but low in the edematous pancreatitis group, with significant differences between the two groups, especially in the DNase II levels over a 36-h period (p less than 0.05-0.01). Therefore, these results suggest that serum DNase levels reveal the necrotizing changes in pancreatic parenchyma.
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PMID:Relationship between pancreatic enzymes and pathological changes in the pancreas in acute pancreatitis. The significance of determination of serum deoxyribonuclease. 247 54

A differential Giemsa staining between sister chromatids was obtained by treating chromosomes replicated twice in medium containing 5-bromodeoxyuridine (BrdU) with Hoechst 33258 plus black light at 55 degrees C (HB pretreatment) and deoxyribonuclease (DNase) I, II, or micrococcal nuclease. In this staining pattern the BrdU bifilarly substituted chromatids were darkly and the unifilarly substituted chromatids lightly stained. This staining pattern was obtained only by staining the HB-DNase I-treated chromosomes with Giemsa and methylene blue, not by several other dyes tested. Relatively more DNA labelling was removed from the non-BrdU-substituted than the BrdU-substituted chromosomes, when the HB-pretreated chromosomes were digested with DNase I. But the protein labelling was not removed appreciably in the same treatment. The differential DNase I sensitivity between the non-BrdU-substituted and BrdU-substituted chromosomes disappeared when the HB-pretreated chromosomes were incubated with proteinase K before The DNase I digestion. Moreover, no differential DNase I sensitivity was found between the HB-pretreated isolated DNA containing and not containing BrdU. We propose that during the HB pretreatment, more DNA-protein cross-linkings are induced in BrdU bifilarly substituted than the unifilarly substituted chromatids. This structure protects the chromosomal DNA against the DNase I digestion. Thus, a reverse differential Giemsa staining between sister chromatids is obtained by the HB-DNase I treatment.
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PMID:Reverse differential staining of sister chromatids induced by Hoechst plus black light and endonuclease. 257 33

Nuclei from confluent and mitotically arrested populations of human diploid fibroblast-like cells were subjected to digestion by micrococcal nuclease and deoxyribonuclease (DNase I) following the removal of various histone components by salt extraction. There was no age or culture state variation in the susceptibility of DNA to micrococcal nuclease digestion. There was an age related inhibition of DNA digestion by DNase I in nuclei from older confluent cells before and after the removal of H1 histone but not after the removal of core particle histones. This inhibition was not detected in older arrested populations. These results indicate that an age-related masking by nucleosome core histones may limit the accessibility of DNA to enzymatic activities in older confluent cells. Since this inhibition was absent in older arrested populations, the importance of limited DNA accessibility as a primary cause of cellular senescence is questionable.
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PMID:The effects of histones, in vitro age, and culture state on the digestion of DNA by micrococcal nuclease and deoxyribonuclease I. 622 86

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.
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PMID:Purification and characterization of the Ca2+ plus Mg2+-dependent endodeoxyribonuclease from calf thymus chromatin. 626 Jul 59

The three-dimensional structure of bovine pancreatic deoxyribonuclease I (DNase I) has been determined at 2.5 A resolution by X-ray diffraction from single crystals. An atomic model was fitted into the electron density using a graphics display system. DNase I is an alpha, beta-protein with two 6-stranded beta-pleated sheets packed against each other forming the core of a 'sandwich'-type structure. The two predominantly anti-parallel beta-sheets are flanked by three longer alpha-helices and extensive loop regions. The carbohydrate side chain attached to Asn 18 is protruding by approximately 15 A from the otherwise compact molecule of approximate dimensions 45 A X 40 A. The binding site of CA2+-deoxythymidine-3',5'-biphosphate (Ca-pdTp) has been determined by difference Fourier techniques confirming biochemical results that the active centre is close to His 131. Ca-pdTp binds at the surface of the enzyme between the two beta-pleated sheets and seems to interact with several charged amino acid side chains. Active site geometry and folding pattern of DNase I are quite different from staphylococcal nuclease, the only other Ca2+-dependent deoxyribonuclease whose structure is known at high resolution. The electron density map indicates that two Ca2+ ions are bound to the enzyme under crystallization conditions.
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PMID:Three-dimensional structure of bovine pancreatic DNase I at 2.5 A resolution. 649 35

Essentially all of the DNA polymerase alpha activity in CV-1 monkey cells could be extracted as an enzyme complex that used DNA substrates with a low primer:template ratio, such as denatured DNA, at least 25 times more efficiently than did purified alpha polymerase. This form of the enzyme was rapidly dissociated either by the nonionic detergent Triton X-100 or by chromatography on phosphocellulose to generate alpha polymerase and its protein cofactor complex, C1C2. Both alpha polymerase and C1C2 were then independently purified free of deoxyribonuclease, RNA polymerase, DNA ligase, and ATPase activities, and the C1C2 complex was shown to consist of at least two proteins. Purified C1C2, which exhibited no DNA polymerase activity, completely restored the ability of alpha polymerase to use denatured DNA. Although high concentrations of denatured DNA inhibited the activity of C1C2, which binds tightly to single-stranded but not double-stranded DNA, low concentrations catalyzed reconstitution of alpha polymerase with C1C2. The resulting enzyme complex was chromatographically distinct from alpha polymerase on DEAE-Bio-Gel, was no longer dependent upon addition of C1C2 in order to utilize denatured DNA as effectively as DNase I-activated DNA, and was not inhibited by high concentrations of denatured DNA. These properties of the purified reconstituted enzyme were indistinguishable from those native alpha X C1C2-polymerase.
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PMID:Preparation of DNA polymerase alpha X C1C2 by reconstituting DNA polymerase alpha with its specific stimulatory cofactors, C1C2. 688 71

Nuclei and chromatin isolated in the presence of calcium or magnesium from Rana catesbeiana liver tissue exhibit considerable endogenous deoxyribonuclease activity. This activity is present in liver nuclei isolated from froglets as well as in liver nuclei isolated from untreated and thyroid hormone treated premetamorphic tadpoles. Nuclei and chromatin isolated in the absence of divalent cations and in the presence of spermine exhibit no detectable expression of the endogenous deoxyribonuclease activity. The endogenous deoxyribonuclease present, but not expressed, in spermine-isolated tadpole liver nuclei or chromatin is salt extractable. Once dialyzed, the salt-extracted deoxyribonuclease is activated by calcium or magnesium. This deoxyribonuclease shows maximal enzyme activity in 15 mM calcium at pH 8.0 or in 15 mM magnesium at pH 7.4. After Ca2+ activation, deoxyribonuclease activity is maximally inhibited by amounts of spermine similar to that required to completely inhibit DNase I. Destruction of the salt-extracted deoxyribonuclease activity by treatment with proteinase K or heat suggests that it is of a proteinaceous nature. The localization and nature of this enzyme activity established that it is associated with the salt-soluble proteins affiliated with tadpole and froglet liver chromatin.
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PMID:Chromatin-associated deoxyribonuclease activity in liver nuclei isolated from Rana catesbeiana froglets and premetamorphic and T3-induced tadpoles. 697 71

An endodeoxyribonuclease has been purified to near homogeneity from rat small intestinal mucosa by a procedure involving Con A-Sepharose affinity chromatography. During the initial steps of purification, the presence of 5 mM CaCl2 was essential for stability of the enzyme activity. The enzyme has a molecular weight of 32 000 and an isoelectric point of 4.7. NaCl, sulfhydryl reagents, and iodoacetate strongly inhibited the reaction, but tRNA did not. The enzyme required divalent cations for activity and had a pH optimum of pH 6.2 with Co2+ and pH 7.7 with Mn2+. In both optimum conditions, the enzyme hydrolyzed native DNA more rapidly than denatured DNA, and the average chain lengths of limit digestion products of native and denatured DNA were 8 and 10, respectively, at pH 6.2 and 9 and 11, respectively, at pH 7.7. The enzyme activity to produce acid-soluble fractions from linear DNA substrate was similar in the two optimum conditions, but the activity to nick double-stranded, superhelical circular DNA substrate was significantly higher at pH 6.2 than at pH 7.7. The endonuclease formed single-strand breaks making 5'-phosphoryl and 3'-hydroxyl termini, and deoxythymidine was present at the 5' termini with a frequency of about 50% in both optimum conditions. Bovine pancreatic DNase I antibody and G-action inhibited the enzyme activity. Thus this endonuclease is classified as a DNase I.
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PMID:Purification and properties of a neutral endodeoxyribonuclease from rat small intestinal mucosa. 707 91


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