Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.22.1 (DNase II)
 429 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

It was revealed by means of nucleoprotein-celite-chromatography that DNA-protein interactions in the chromatin fraction sensitive to micrococcal nuclease and DNase II are weaker that in the resistant one. The micrococcal nuclease destroys the DNA-matrix bond resistant to salt-urea, while DNase II does not change the DNA-matrix integrity. Tightness of the DNA-protein interactions is weakened by the increasing chromatin fragmentation, but does not depend on the size of chromatin particles.
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PMID:[Stability of DNA-protein interactions in chromatin fractions with different sensitivity to nucleases]. 323 Dec 30

A trypsin inhibitor was isolated from mouse lymphocytic leukemia L 1210 cells by ammonium sulphate precipitation and preparative isoelectric focusing. A 39-fold purification was attained. The inhibitor is a protein since its activity is destroyed by pronase and it binds to insolubilized trypsin. Two main forms of the inhibitor were found of pH 4.8 and 5.3. The inhibitor is copurified with DNA, although neither DNase II nor RNase A change its activity.
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PMID:Serine proteinase inhibitor from lymphocytic leukemia cells. Properties and copurification with DNA. 325 33

In the presence of 3 mM MgCl2 DNase I cleavage of bulk, globin and ovalbumin gene chromatin in chicken erythrocyte nuclei generates fragments which are multiples of a double-nucleosome repeat. However, in addition to the dinucleosomal periodicity beta-globin gene chromatin was fragmented into multiples of a 100 b.p. interval which is characteristic for partially unfolded chromatin. This distinction correlates with higher sensitivity of beta-globin domain to DNase I and DNase II as compared to the inactive ovalbumin gene. At 0.7 mM MgCl2 where these DNases fragment bulk chromatin into series of fragments with a 100 b.p. interval, the difference in digestibility of the investigated genes is dramatically decreased. When chromatin has been decondensed by incubation of nuclei in 10 mM Tris-buffer, DNase II generates a typical nucleosomal repeat, and the differential nuclease sensitivity of the analyzed genes is not observed. The data suggest that higher nuclease sensitivity of potentially active genes is due to irregularities in higher order chromatin structure.
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PMID:A structure of potentially active and inactive genes of chicken erythrocyte chromatin upon decondensation. 341 26

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.
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PMID:Stimulation of human neuroblastoma DNA polymerase alpha and primase activities by a protein factor isolated from rat liver chromatin. 354 Sep 37

The contact points of transcription factor IIIA with the internal control region of the 5 S RNA gene of Xenopus have been investigated by probing the accessibility of the DNA in the protein-DNA complex to dimethylsulphate and to micrococcal nuclease. The results of quantitative measurements, combined with those from earlier DNase I and DNase II protection studies, are consistent with a series of multiple contacts about five base-pairs apart, or half a double-helical turn, along the whole length of the internal control region. The nine patches of contact we have mapped could correspond to nine DNA-binding fingers in the protein. A model for the overall geometry of the interaction is presented in which the protein lies on one face of the DNA double helix.
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PMID:Mapping of the sites of protection on a 5 S RNA gene by the Xenopus transcription factor IIIA. A model for the interaction. 356 Feb 27

DNA repair replication has been previously demonstrated to occur in mouse spermatocytes during the pachytene stage. The results reported in this study provide a more detailed characterization of pachytene repair by focusing upon specific properties of the sites of replication. Our data demonstrate that single-strand breaks persist within replicated sequences throughout a period which corresponds to a defined interval of the pachytene stage. A large fraction of the sites may be nicked more than once within the same DNA strand, allowing the selective release of replicated DNA sequences from gently denatured spermatocyte DNA. DNA fragments thus prepared from pachytene spermatocytes are not of random sequence composition, but are derived from a specific subset of the mouse genome. Sites of replication are also associated with chromatin of distinctive structure in pachytene spermatocytes, as evidenced by the sensitivity of replicated chromatin to DNase II, and its solubility in the presence of Mg2+. In each of these respects, sequences replicated in pachytene spermatocytes closely resemble their counterparts in the Lilium genome.
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PMID:DNA synthesis at selective sites during pachytene in mouse spermatocytes. 373 43

This study examines the relationship between unbalanced growth, DNase II activity, DNA breakage and cell survival during the exposure of L5178Y cells to hydroxyurea (HU), excess thymidine (dThR) or HU with excess of four deoxyribonucleosides (dNR). It has been found that in the cells arrested by HU or dThR, but still appearing viable with the trypan blue exclusion test, Protein/DNA imbalance and abnormal cell volume are correlated with enhancement of DNase II activity in the cells and in the medium and with moderate increase in parental DNA breakage. The incidence of DNA breaks was markedly potentiated in the presence of non-toxic concentration of caffeine (CAF), used to inhibit DNA repair. In HU+dNR arrested cells, in which unbalanced growth was abolished, enhancement of DNase II activity and of DNA breakage in the presence or absence of CAF was substantially prevented. Comparison of posttreatment cell survival in the presence or absence of CAF confirmed the differential effect of CAF: while in HU or dThR arrested cells the presence of CAF induced marked cell killing, in HU+dNR arrested cells the influence of CAF was negligible. Only a slight effect of CAF was observed in cells in which dThR-induced arrest and unbalanced growth were reversed by deoxycytidine (dCR) addition. It is suggested that the involvement of DNA nucleases in the unbalanced growth-induced overproduction of numerous hydrolytic enzymes, with their progressive leakage through the cell membranes, can lead to progressive DNA digestion. DNA breaks produced in this way are normally, at least partly, repaired. Concomitant exposure of such cells to DNA repair inhibitor can markedly enhance the level of breaks, leading to potentiation of unbalanced growth-induced cell killing.
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PMID:Mechanism of unbalanced growth-induced cell damage. II. A probable relationship between unbalanced growth, DNA breakage and cell death. 377 83

The process of chromatin compactization in nuclei at different concentrations of Mg2+ and/or Na+ ions has been investigated by analysis of chromatin cleavage pattern with DNase II. Nuclei of cells that differ in transcriptional activity and have different nucleosome DNA repeat length such as pigeon erythrocytes, rat cerebellum neurons and pigeon brain cortex neurons were studied. In the presence of 0-3 mM MgCl2 several compactization levels of nucleosomal fiber were revealed in chromatin of pigeon erythrocyte and rat cerebellum nuclei (nucleosome DNA repeat of 210 +/- 3 and 202 +/- 3 nucleotide pairs, respectively). Each of these levels are characterized by different types of periodical DNA fragmentation of chromatin with DNase II, namely formation of nucleosomal, "half-nucleosomal" (fragmentation via a 100 nucleotide pairs interval), and dinucleosomal periodicities. Similar compactization stages were shown also for isolated erythrocyte chromatin. In 0-3 mM MgCl2 chromatin of pigeon brain cortex neuron nuclei having nucleosome DNA repeat size 164 +/- 3 nucleotide pairs is cleaved with DNase II producing only a "half-nucleosomal" periodicity. A pattern of chromatin fragmentation was compared in the presence of Na+ and Mg2+ ions. In the presence of 10-100 mM NaCl or in 0.1-3 mM MgCl2 but in the presence of 50 mM NaCl erythrocyte chromatin condenses in nuclei forming a structure which is characterized only by a "half-nucleosomal" periodicity of fragmentation at DNase II action. Upon higher NaCl concentration (100-400 mM) in the presence of 3 mM MgCl2 a transition from dinucleosomal fragmentation to nucleosomal fragmentation of erythrocyte chromatin in nuclei with DNase I was observed.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Structural organization of the nucleosomal chromatin fibril under various ionic conditions]. 380 10

The (Rp)- and (Sp)-diastereoisomers of thymidyl 3'-(4-nitrophenyl phosphorothioate) (1) were found to act as unusual substrates for acid deoxyribonuclease (DNase II). Instead of the expected thymidine 3'-phosphorothioate, the product resulting from the reaction of (Rp)-1 catalyzed by DNase II was identified as (Sp, Rp)-thymidyl (3'-5')thymidyl phosphorothioate 3'-(4-nitrophenyl phosphorothioate), while that from (Sp)-1 has been recognized as a 10:1 mixture of (Sp, Rp)-thymidyl (3'-5')thymidyl phosphorothioate 5'-(4-nitrophenyl phosphorothioate) and (Rp, Sp)-thymidyl (3'-5')-thymidyl phosphorothioate 3'-(4-nitrophenyl phosphorothioate), respectively. Both types of transnucleotidylations were found to occur with retention of configuration at phosphorus. Stereochemical results may be interpreted in terms of two step mechanisms involving the formation of the intermediate, covalent substrate enzyme complexes.
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PMID:Activity of acid deoxyribonuclease towards diastereoisomers of thymidyl 3'-(4-nitrophenyl phosphorothioate). Stereochemistry of transnucleotidylation reaction. 394 Oct 94

An acid DNase (DNase II) from porcine spleen was purified by sequential chromatography over carboxymethyl-cellulose, blue dextran-Sepharose, hydroxylapatite, and sulfoxyethyl-cellulose. The purified enzyme shows two polypeptide bands on sodium dodecyl sulfate-polyacrylamide gel electrophoresis at Mr 35,000 (alpha chain) and 10,000 (beta chain). The sum of the two molecular weights is that of the native enzyme (45,000). Thus, the DNase II molecule is an alpha,beta dimer. The two polypeptides are not joined by disulfide bonds, but can be cross-linked chemically with dimethyl suberimidate. They are dissociable in 8 M urea, after which they can be isolated by gel filtration on Sephadex G-100, eluting with 1 M acetic acid. Once dissociated, the two polypeptides cannot be reassociated to regenerate DNase II activity. The sum of the amino acid compositions of the two polypeptides is that of the native enzyme, and both contain carbohydrate. The beta chain is devoid of histidine, half-cystine, valine, and methionine. The NH2-terminal amino acid of the alpha chain is leucine, while that of the beta chain cannot be identified by either dansylation or Edman degradation. Alkylation of an essential histidine residue of DNase II occurs on incubation of the enzyme with [2-14C] ICH2COOH (Oshima, R. G., and Price, P. A. (1973) J. Biol. Chem. 248, 7522-7526). Radioactivity is found only in the alpha chain. After hydrolysis of the alpha chain with trypsin, chymotrypsin, and thermolysin, radioactive peptides were isolated by gel filtration on Sephadex G-25 and reversed-phase high performance liquid chromatography. Sequence analyses of the radioactive peptides show alkylation of 1 of 9 histidines in the entire amino acid sequence of DNase II. The sequence around this histidine, determined by manual microsequencing and by the release of amino acids with carboxypeptidases A and B, is Ala-Thr-Glu-Asp-His-Ser-Lys-Trp.
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PMID:The subunit structure and active site sequence of porcine spleen deoxyribonuclease. 403 Jul 66


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