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:3.1.22.1 (DNase II)
429 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Methylation of a calf thymus DNA substrate by dimethyl sulphate (DMS) leads to an inhibition of deoxyribonuclease II activity which is gradually lost with time. The extent of this initial inhibition is linearly related to the amount of methylated products in DNA and quantitatively similar effects were found when the enzyme was used under either acid or neutral conditions. Deoxyribonuclease II was shown to produce 3'-phosphate termini under both acid and neutral conditions and thus, irrespective of the ionic conditions for the action of this enzyme in vivo the effects demonstrated here are of potential significance. Local denaturation of the methylated DNA may be partly responsible for these inhibitory effects but it is likely that the methyl purines also play a more direct role.
...
PMID:Resistance of alkylated DNA to degradation by deoxyribonuclease II at neutral and acid pH. 0 18

The four histones H2A, H2B, H3 and H4 from calf thymus, CHO and sea urchin gastrula cells were associated by stepwise dialysis from 2 M NaCl with SV40 DNA Form I. The in vitro-assembled chromatins were visualized by electron microscopy and the size of the DNA fragments generated by digestion with DNase II was determined. Irrespective of the origin of the histones, the size of the smallest DNA band generated at early times of digestion was about 190 base pairs, whereas oligomeric DNA bands were multiples of 140 bp. These results support our previous proposal that the four histones H2A, H2B, H3 and H4 are able to organize more than 140 bp of DNA, but do not provide any evidence that the variability of histones H2A and H2B plays a role in the variability of the DNA repeat length of native chromatins.
...
PMID:The same amount of DNA is organized in in vitro-assembled nucleosomes irrespective of the origin of the histones. 21 59

The following procedures have been used to prepare fifteen modified dinucleoside monophosphates: (a) bisulfite-catalyzed transamination with aniline to give an N4-phenylcytidine (CPh), (b) bisulfite-catalyzed transamination with beta-naphthylamine to give an N4-beta-naphthylcytidine (CbetaN), (c) alkylation with 7-bromomethylbenz[a] anthracene to afford a 7(benz[a]anthryl-7-methyl)guanosine (GMBA), and (d) reaction with N-acetoxy-2-acetylaminofluorene to give an 8-(N-2-fluorenylacetamido)guanosine (GAAF). The compounds prepared were A-CPh, CPh-A, CPh-G, U-CPh, CPh-U, A-CbetaN, CbetaN-A, G-CbetaN, CbetaN-G, U-CbetaN, CbetaN-U, GMBA-U, U-GMBA, GAAF-U, and U-GAAF. All of the modified compounds were hydrolyzed to the expected monomers with venom and spleen exonucleases. Hydrolysis by micrococcal nuclease was inhibited in the following cases: A-CPh, A-CbetaN, U-GMBA, and U-GAAF. The first three reactions above were applied to denatured calf thymus DNA to prepare modified DNA samples containing from 0.3 to 2.0% bound aromatic residues. The modified nucleic acids were completely hydrolyzed to nucleosides by the combination of venom exonuclease, deoxyribonuclease I and alkaline phosphatase. The same results were obtained with a combination of spleen exonuclease, deoxyribonuclease II, and alkaline phosphatase. Hydrolysis of the modified nucleic acids by micrococcal nuclease and alkaline phosphatase afforded primarily nucleosides, with some dinucleoside monophosphates. The amount of the latter did not exceed that found in the hydrolysis of control DNA, however. Other workers have observed inhibition of enzymatic hydrolysis of nucleic acids modified by aromatic carcinogens. We postulated that their results may have been caused by cross-links, which were avoided in our studies.
...
PMID:Preparation and enzymatic hydrolysis of dinucleoside monophosphates and DNA modified with aromatic residues. 55 43

Survival time of mice after i.v. injections of 2,4.6-triethylene-imino-1,3,5-trazine (TEM) or total body-X-irradiation (TBI) was increased by 6-methyluraclil (6-MU) when given in food (200 ppm). Under the same conditions, 6-MU decreased the involution of spleen and thymus (as measured by DNA-content and DNase II activity) under the infuence of TEM and enhanced the regeneration of the spleen after TBI. Elevation of DNase I- and protein content of the kidneys and a (short-dated) increase of incorporation of 14C-phenylalamine into microsomes of liver of 14C-orotic acid into RNA of liver and kidney suggest that the influence of 6-MU is mediated at least partly by a specfically anabolic effect.
...
PMID:E1On the effect of 6-methyluracil on mice damaged by 2,4,6-triethylene-imino-1,3,5-triazine or by X-irradiation (author's transl). 57 13

It has been demonstrated by digestion studies with micrococcal nuclease that reconstitution of complexes from DNA and a mixture of the four small calf thymus histones H2A, H2B, H3, and H4 leads to subunits closely spaced in a 137 +/- 7-nucleotide-pair register. Subunits isolated from the reconstituted complex contain nearly equimolar amounts of the four histones and sediment at 11.6S. On DNase I digestion both the reconstituted complex and the separated subunits gave rise to series of single-stranded DNA fragments with a 10-nucleotide periodicity. This indicates that the reconstitution leads to subunits very similar to nucleosome cores. Nucleosome cores closely spaced in a 140-nucleotide-pair register were also obtained upon removal of histone H1 from chromatin by dissociation with 0.63 M NaCl and subsequent ultracentrifugation. In reconstitution experiments with all five histones (including histone H1) our procedure did not lead to tandemly arranged nucleosomes containing about 200 nucleotide pairs of DNA. In the presence of EDTA, DNase II cleaved calf thymus nuclei and chromatin at about 200-nucleotide-pair intervals whereas in the presence of Mg2+ cleavage at intervals of approximately half this size was observed. The change in the nature of the cleavage pattern, however, was no longer found after removal of histone H1 from chromatin. This indicates that H1 influences the accessibility of DNase II cleavage sites in chromatin. This finding is discussed with respect to the influence of histone H1 on chromatin superstructure.
...
PMID:Closely spaced nucleosome cores in reconstituted histone.DNA complexes and histone-H1-depleted chromatin. 63 Nov 38

Recent interest in the use of adriamycin-DNA complex as an approach to improve the therapeutic effectiveness and to reduce toxicity of adriamycin for cancer chemotherapy requires an in-depth understanding of the physicochemical and biochemical properties of such complexes. The interactions of adriamycin with single-strand polydeoxyribonucleotides, double-strand DNA, and double-strand ribodeoxyribopolynucleotide hybrids were therfore investigated. Association constants (Kapp) of adriamycin and polynucleotides were obtained. These data showed that the inherent variable in such complex lies in the composition of the polynucleotides. Alternate deoxyguanylate (dG)-deoxycytidylate (dC) sequence binds 7-fold better than alternate deoxyadenylate (dA)-deoxythymidylate (dT) sequence. Comparative studies of the hydrolysis of DNA duplexes by deoxyribonucleases I and II with and without adriamycin were also carried out. The rate of hydrolysis decreased in the order poly(dA-dT) greater than calf thymus DNA greater than poly(dG-dC) greater than poly(dA)-poly(dT) greater than poly(dG)-poly(dC) for DNase I and poly(dA)-dT) greater than calf thymus DNA greater than poly(dG-dC) greater than poly(dA)-poly(dT) greater than poly(dG)-poly(dC) for DNase II. Intercalation of adriamycin to deoxyribopolynucleotide duplex resulted in inhibition of DNase II two to three times more than tat of DNase I. On the other hand, intercalation of adriamycin to homodeoxypolynucleotide duplex poly(dA)-poly(dT) and poly(dG)-poly(dC) enhanced the DNase I hydrolysis. If DNase I activity could be related to serum DNase and DNase II related to tumor lyososomal DNase as in the endocytosis mechanism proposed by Trouet et al. (Cancer Chemotherapy Rept., 59: 260, 1975), the best adriamycin carrier suggested by this investigation could be poly(dA)-poly(dT) and poly(dG-dC). It is also suggested in this study that adriamycin-RNA-DNA hybrid could be of interest as an antiviral agent by a similar release mechanism via RNase H, an enzyme associated with viral reverse transcriptase.
...
PMID:Effect of deoxyribonuclease on adriamycin-polynucleotide complexes. 97 96

The effects of spermine, putrescine, and spermindiol on different nucleases were investigated. A highly active spermine analog, spermindiol, was synthesized, which markedly enhanced DNA hydrolysis by staphylococcal nuclease and spleen DNase II [EC 3.1.4.6] and RNA degradation by staphylococcal nuclease and pancreatic RNase A [EC 3.1.4.22]. Spermindiol also increased the melting temperature of calf thymus DNA.
...
PMID:A potent polyamine analog, spermindiol. 101 Aug 53

The time course of the fragmentation of calf thymus chromatin by DNase II (deoxyribonucleate 3'-oligonucleotidohydrolase, EC 3.1.4.6) has been examined by sedimentation of chromatin digests through linear (5-20%) sucrose gradients. The action of nuclease is decidedly nonrandom, ultimately producing roughly equal amounts of acid-soluble oligonucleotides and 11S nucleoprotein particles. The 11S particles contain double-stranded DNA that is approximately 400 A or 120 base-pairs long, as measured by electron microscopic examination of deproteinized samples, and is maintained in a compact conformation within the intact particles. In addition, 15S nucleoprotein particles containing predominantly 800-A lengths of DNA have been isolated from less extensively digested chromatin. Evidence is presented which indicates that the 11S particles are fundamental structural units that are arranged in tandem along certain regions of chromatin fibrils. Preliminary experiments with different nucleases and with chromatin from different mammalian species indicate that these results are a natural consequence of the arrangement of DNA and proteins in mammalian chromatin and are not peculiar to the system described in detail.
...
PMID:Nucleas action on chromatin: evidence for discrete, repeated nucleoprotein units along chromatin fibrils. 105 45

Phosphorus-31 NMR has been applied to the characterization of terminal phosphates on fragments of calf thymus DNA induced by three different nuclease systems: DNase I, DNase II and the artificial nuclease 'Mn-TMPyP/KHSO5'. In this last case, the oxidative damage to deoxyribose leads to two monophosphates esters (at the 3' and 5' ends) on both sides of the cleavage site. This method constitutes a promising approach to visualise the phosphate termini generated in DNA or RNA cleavage by cytotoxic drugs or chemical nucleases and provides a novel insight into the molecular aspects of their mechanism of action.
...
PMID:31P NMR characterization of terminal phosphates induced on DNA by the artificial nuclease 'Mn-TMPyP/KHSO5' in comparison with DNases I and II. 205 47

Nuclear protein factor type 1 (NPF-1) that simulates IMR-32 primase-associated DNA polymerase alpha 1 and alpha 2 activities has been purified from a high-salt extract of liver chromatin from 6-month-old rats. The final purified factor lacks DNA polymerase alpha, RNA polymerase, and DNA-unwinding or topoisomerase type I activities. The stimulatory activity is destroyed by trypsin (60 min at 37 degrees C), DNase II (60 min at 37 degrees C), and heat treatment (2 min at 68 degrees C). The 125I-labeled NPF-1 does not bind to activated calf thymus DNA or poly(dC). However, it forms a ternary complex with DNA in the presence of DNA polymerase alpha-primase complex (alpha 1 and alpha 2). The ternary complex sediments on sucrose density gradient as a heavier band (11S). The NPF-1 also stimulates (2.5-fold) primase-catalyzed incorporation of GMP and dGMP from the corresponding triphosphates on poly(dC) template even in the presence of a high concentration of alpha-amanitin (400 micrograms/ml). The labeled duplex containing the poly(dC) template, [32P]-GTP, and [3H]dGTP loses 80% of the 32P label and 70% of the 3H label after treatment with 0.3 M KOH and DNase I, respectively. The products were isolated from reaction mixtures incubated with and without NPF-1 and subjected to alkaline sucrose-density-gradient sedimentation analysis. The results suggest that the rate of synthesis of DNA short chains is increased in the presence of NPF-1 without a concomitant increase in the chain length of the newly synthesized products.
...
PMID:Stimulation of human neuroblastoma DNA polymerase alpha and primase activities by a protein factor isolated from rat liver chromatin. 354 Sep 37


1 2 3 Next >>

---