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

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Query: EC:3.1.21.1 (DNase)
7,655 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A 250-fold purified ATP-dependent DNase from Bacillus cereus has been separated to DNA-dependent ATPase I and II and a DNase specific for single-stranded DNA (ssDNase) by means of high resolution of DEAE cellulose chromatography. Simultaneously with the separation of ATPase and ssDNase, a decrease in ATP-dependent DNase activity was observed. Complete separation resulted in the total loss of ATP-dependent DNase activity. Reconstitution of ATP-stimulated DNase activity was dependent on the ratio of the combined ATPase II and ssDNase.
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PMID:Separation of ATP-dependent DNAse to ATPase and DNAse. 645 34

We have recently demonstrated by electron microscopic cytochemical methods that unfixed human fibroblasts exhibit intense MG2+ dependent adenosine triphosphatase (nATPase) activity in circumscribed areas of the cell nucleoli. The nATPase was specific for ATP and dATP and was inhibited by other ribonucleoside triphosphates. Its intranucleolar localization relative to nucleolar chromatin, and segregation into nucleolar zones after actinomycin treatment of the cells, suggested that the reaction took place in fibrillar centers. This ATPase has now been further characterized by electron microscopic cytochemistry. It was determined that short fixation permitted retention of most of the ATPase activity, and that the enzyme was active at high ionic strength (up to 400 mM KCl), but that the enzyme activity was very sensitive to elevated temperatures. DNA dependence of the enzyme was shown by inhibition of the reaction by DNase pretreatment in parallel with the removal of DNA from the cell, while pretreatment with RNase had no significant effect. The nATPase activity was also selectively inhibited by treatment of the cells with antagonists of the B subunit of DNA gyrase, novobiocin, and coumermycin, but not by nalidixic or oxolinic acids, which interfere with the A subunit of gyrase. Inhibitors of RNA synthesis, actinomycin D and aminonucleoside of puromycin, potentiate rather than inhibit nATPase reaction. The results suggest that nATPase functions to alter the degree of supercoiling or catenation of nucleolar organizer DNA, and is in reality a DNA topoisomerase that hydrolyzes ATP during its action.
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PMID:DNA dependence and inhibition by novobiocin and coumermycin of the nucleolar adenosine triphosphatase (ATPase) of human fibroblasts. 646 Aug 2

We have used liposomes to deliver DNAase I inside normal Syrian hamster embryo (SHE) cells. We showed the entrance of DNAase I inside the cell by dose-dependent cytotoxicity; and the entrance of DNAase I into the nucleus by the induction of chromosomal aberrations and somatic mutation at the HPRT locus (but not at the Na+/K+ ATPase locus). The induction of neoplastic transformation in cultures treated by DNAase I-in-liposomes was manifested by increased saturation density, colony formation at low seeding density, colony formation in 1% serum and 0.3% agar, and tumorigenicity in 100% of injected animals. The acquisition of anchorage-independent growth became apparent only after 39-57 posttreatment population doublings. Thus damage to DNA alone can initiate the neoplastic transformation process; but for full expression of the neoplastic phenotypes, a long progression time is required for the acquisition of anchorage-independent growth and tumorigenicity.
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PMID:DNAase I encapsulated in liposomes can induce neoplastic transformation of Syrian hamster embryo cells in culture. 650 50

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

An ATP-dependent DNAase has been purified to homogeneity from extracts of Alcaligenes faecalis, and has been shown to couple the degradation of DNA to the hydrolysis of ATP. Enzyme activity also requires divalent ions, with Mn2+, Mg2+ and Co2+ being effective cofactors for both DNAase and ATPase activities. We have studied the intermediates formed by the enzyme during the degradation of duplex DNA with each of these cofactors using sedimentation velocity, binding to nitrocellulose filters and sensitivity to a nuclease specific for single-stranded DNA. With Mn2+ or Co2+, the enzyme acts processively to produce mostly acid-soluble material and acid-insoluble single-strand fragments up to 400-nucleotides long. However, with Mg2+ present, the enzyme produces intermediates comprising a duplex region with one or more single-strand tails, while little acid-soluble oligonucleotide is formed. From these results, we propose a model to describe the mechanism by which the ATP-dependent DNAase from A. faecalis degrades duplex DNA.
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PMID:Studies on the mechanism of action of the ATP-dependent DNAase from Alcaligenes faecalis. 721 56

An ATP-dependent deoxyribonuclease has been partially purified from extracts of Caulobacter crescentus cells in a procedure involving ion-exchange and affinity chromatography. The enzyme was purified approximately 350-fold and was free of contaminating nucleolytic and ATPase activity. The nuclease hydrolyzes linear, double-stranded DNA with subsequent release of short oligonucleotides, mostly from one to four bases in length. The release of nucleotides is accompanied by hydrolysis of ATP, 7.6 nmol ATP being consumed for each nmol of acid-soluble products of DNA degradation. The enzyme shows an absolute requirement for divalent cations and in most active at pH 7.6 to 8.8. The molecular weight of the nuclease, estimated by gel filtration and sucrose density gradient centrifugation, is 280 000.
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PMID:Purification and some properties of ATP-dependent deoxyribonuclease of Caulobacter crescentus. 728 94

An ATP-dependent deoxyribonuclease was isolated from lymphocyte nuclei. The enzyme preparation sediments with about 4 S through sucrose gradients and shows one stainable band after sodium dodecyl sulfate gel electrophoresis. We find three, possibly four, activities associated with the enzyme: a DNA-independent ATPase activity; an ATP-independent endonuclease; an ATP-dependent nuclease which degrades nicked DNA to acid-soluble material; and an unwinding activity producing single-stranded regions in nicked DNA.
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PMID:A lymphocyte ATP-dependent deoxyribonuclease. Isolation and properties. 730 58

The protease subtilisin has been reported to cleave skeletal muscle G-actin between Met 47 and Gly 48 generating a core fragment of 33 kDa and a small N-terminal peptide, which remains attached to the core fragment [Schwyter, D. Phillips, M., & Reisler, E. (1989) Biochemistry 28, 5889-5895]. However, amino acid sequencing and mass spectroscopy of subtilisin cleaved-actin revealed two cleavage sites, one between Met 47 and Gly 48 and a second between Gly 42 and Val 43, generating an actin core of 37 kDa and a nicked 4.4 kDa N-terminal peptide. Here we describe a procedure for purifying the actin core fragment and the attached N-terminal peptide from the linking pentapeptide comprising amino acid residues 43-47 under native conditions by anion exchange chromatography. After removal of the pentapeptide, the salt-induced polymerization of actin was abolished. However, the purified fragments could be polymerized by addition of salt plus myosin subfragment 1 or salt plus phalloidin as shown by sedimentation and fluorescence increase using N-(1-pyrenyl)iodoacetamide labeled actin. These results confirm earlier reports proposing that cleavage in the DNase I binding loop is affecting the ion induced polymerization of actin [Higashi-Fujime, S., et al. (1992) J. Biochem. (Tokyo) 112, 568-572; and Khaitlina, S., et al. (1993) Eur. J. Biochem. 218, 911-920]. Monomeric and filamentous subactin exhibited reduced abilities to inhibit deoxyribonuclease I (DNase I) and to stimulate the myosin subfragment 1 ATPase activity. Direct binding of subactin to DNase I was verified by gel filtration and to myosin subfragment 1 by affinity chromatography, chemical cross-linking, and electron microscopy.
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PMID:Purification and characterization of subtilisin cleaved actin lacking the segment of residues 43-47 in the DNase I binding loop. 757 93

We reported previously on ADP-ribosylation of actins by chicken arginine-specific ADP-ribosyltransferase in vitro and in situ and the inhibition of actin polymerization by this modification [Terashima, M., Mishima, K., Yamada, K., Tsuchiya, M., Wakutani, T. & Shimoyama, M. (1992) Eur. J. Biochem. 204, 305-311]. In the present study, we determined amino acid residues of ADP-ribosylation site(s) in globular (G-) and filamentous (F-) actins and examined the molecular basis of the modification of actin. Arginine-specific ADP-ribosylation occurred at Arg28 and Arg206 in G-actin, but only at Arg28 in F-actin. ADP-ribosylation of Arg206, located on the pointed end of the actin molecule, significantly blocked the interaction with deoxyribonuclease I. These results indicate that Arg206 in G-actin may be involved in actin polymerization. ADP-ribosylation of Arg28, located on the outer surface of actin molecule, did not affect the binding activity with myosin subfragment-1, that is thought to interact through the N-terminal amino acid residues of G-actin. ADP-ribosylation at both Arg28 and Arg206 of G-actin had no apparent effect on the intrinsic ATPase activity. We concluded from this study that ADP-ribosylation of Arg206 in G-actin causes the inhibition of actin polymerization, and that ADP-ribosylation of Arg28 occurs in F-actin.
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PMID:ADP-ribosylation of Arg28 and Arg206 on the actin molecule by chicken arginine-specific ADP-ribosyltransferase. 762 77

The interaction of myosin subfragment 1 isoenzyme A2 (S1A2) with Mg(2+)-G-actin was studied. Polarization titrations of 1,5-IAEDANS-Mg(2+)-G-actin and of epsilon ATP-Mg(2+)-G-actin with S1A2 provided evidence that, similar to Ca(2+)-G-actin, the proteins form a tight binary complex. Significant amounts of oligomeric forms of actin in the presence and absence of S1 were not detected. The effect of S1A2 on the rates of nucleotide and metal dissociation and hydrolysis from Mg(2+)-actin was measured. The hydrolysis rate for [gamma-32P]ATP-actin in the G-acto-S1A2 complex (k- = 0.016 s-1) was faster than the rate of 32P liberation from the complex (k- = 0.004 s-1), obtained by measuring the liberation of [32P]orthophosphate from [alpha-32P]ATP-actin in the presence of a large excess of alkaline phosphatase. This indicates that most of actin's ATP was hydrolyzed before it was released to solution and that the dissociating nucleotide was ADP, for which the dissociation rate is higher than that for ATP. In agreement with this mechanism, S1A2 accelerated the dissociation of epsilon ATP but inhibited the dissociation of epsilon ADP from the complex. The activation of actin's ATPase is specific for Mg(2+)-G-actin and does not occur in Ca(2+)-G-actin. The effect of deoxyribonuclease I on the rates of nucleotide dissociation and hydrolysis was examined.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Myosin subfragment 1 activates ATP hydrolysis on Mg(2+)-G-actin. 791 68


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