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 deoxyribonuclease has been purified more than 2000-fold from the green algae, Chlamydomonas reinhardii. The enzyme is most active on denatured DNA. Optimum activity is at pH 8.5, in 80 mM Tris-HCl buffer and 2 mM CaCl2. Other divalent cations can replace Ca2+ with varying lower efficiency. EDTA and inorganic phosphate are strongly inhibitory, while ATP and high concentrations of 2-mercaptoethanol are slightly inhibitory. The molecular weight is approximately 35 000, the Stokes radius is 2.7 nm, and the sedimentation coefficient 2.8 S. It is a single polypeptide chain, and the frictional ratio of 1.27 suggests it is only slightly asymetrical. The isoelectric point is 9.5. This enzyme has been termed exonuclease 1.
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PMID:A deoxyribonuclease from Chlamydomonas reinhardii. 1. Purification and properties. 1 43

DNase A studied by gel filtration on Sephadex G-100 at pH 7.4 in 40 mM Tris-HCl buffer, behaves hydrodynamically as a spherical monomeric macromolecule of around 31,000 molecular weight, with a Stokes radius = 24.7 A, f/fo = 1.19, and D20,W = 8.69. Similar results were obtained by analytical dialysis using zinc chloride-modified cellophane membranes. The elution volume of DNase A decreases as the pH increases between pH 4.7 and pH 9.5. This effect has been attributed to a change in the tridimensional structure of the protein and interpreted as a modification in the axial ratio due to unfolding of the polypeptide chain with increase in the apparent Stokes radius. The addition of Ca2+ produce reversion of the pH-induced changes at pH 9.5. The transition occurs when Ca2+ binds to at least two binding sites (n = 1.66 in a Hill plot) with a Kd = 8.9 X 10(-5) M and the effect appears to be cooperative. These findings support the hypothesis that Ca2+-binding to DNase A causes a conformational change that maintains a more active structure of the enzyme, especially when the pH-induced unfolding reduces its activity.
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PMID:The role of Ca2+ on pH-induced hydrodynamic changes of bovine pancreatic deoxyribonuclease A. 2 82

By sequential acid treatment, gel filtration and KM-cellulose sorption a 18--20-fold purified preparation of ribonuclease with a yield of 50--60% was obtained from the culture liquid filtrate of Actinomyces rimosus 994. The preparation had a high specific activity of 450,000--600,000 units/mg protein, contained 85--98% protein, insignificant amounts of carbohydrates and hydroxytetracycline, and no quantities of DNase, phosphomonoesterases, phosphodiesterase or proteases. In RNA degradation (preparation of the total yeast RNA of the Sigma Co.) optimal results were obtained at 50 degrees C and pH 7.0--7.2 in phosphate buffer and 7.6--8.0 IN Tris-HCl buffer. The preparation was stable at high temperatures (80--100 degrees) in the wide pH range and during storage in the lyophilized form and in buffer solutions. RNase effect was inhibited by zinc, copper, iron and cobalt cations and activated by beta-mercaptoethanol, citrate and EDTA. Protamine sulphate and urea in low concentrations (0.01% and 1--4 M, respectively) accelerated and in high concentrations (1% and 8 M, respectively) terminated the enzyme reaction. With respect to many properties RNase from Act. rimosus 994 was similar to extracellular RNases, produced by other actinomycetes and fungi.
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PMID:[Preparation of extracellular ribonuclease form Actinomyces rimosus 994]. 3 16

A deoxyribonuclease was purified approx. 800-fold from crude extracts of the bacterium Alcaligenes faecalis. The enzyme requires ATP and Mn2+; ATP could be replaced by any other ribo- or deoxyribo-nucleoside triphosphate, and Mn2+ could be replaced by Mg2+ in 0.1 M-Tris/HCl, pH 8.0 at 37 degrees C. The enzyme could degrade linear duplex or denaturated DNA, but was inactive with closed-circular duplex DNA from bacteriophase PM-2. In the course of nucleolytic activity, ATP was hydrolysed. We have measured deoxyribonuclease and adenoxine triphosphatase activity in the presence of various salts, and found that the amount of ATP hydrolysis associated with a given amount of deoxyribonuclease activity was decreased in the presence of tetraethylammonium ions. Since these ions decrease the stability of the DNA helix, we conclude that one function of the ATP hydrolysis is to unwind the DNA.
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PMID:An adenosine triphosphate-dependent deoxyribonuclease from Alcaligenes faecalis. 14 25

The existence of a DNA-dependent protein methylase activity without any concomitant DNA methylase activity was demonstrated in bull seminal plasma. The enzyme utilized S-adenosyl-L-methionine as a methyl donor, and endogenous seminal plasma protein as the substrate. There was no demonstrable enzyme activity when the seminal plasma was preheated at 100 degrees for 10 min, or when the enzyme reaction mixture was incubated at 4 degrees. The protein methylase required a heterologous DNA source, had optimal activity at pH 8.1, and was enhanced in the presence of Mg2+, NH4+, and reduced glutathione. After the methylated protein product was separated from DNA by extraction with 0.2 M HCl, the incorporated radioactivity was shown to be totally solubilized by incubating the protein either with Pronase or 1 M NaOH, while RNase and DNase had no effect. Approximately 70% of the enzymatically synthesized amino acids in the protein product were tentatively identified as O-methylated amino acid ethers by virtue of their elution from a Dowex 50 H+ column with 0.2 M pyridine, and their stability to acid and base hydrolysis. The partially purified methylated product was shown by Sephadex G-50 chromatography to consist of three distinct radioactive proteins with molecular weights of approximately 21,000, 15,000, and 10,000.
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PMID:DNA-dependent protein methylase activity in bull seminal plasma. 24 Mar 99

DNA replication in isolated nuclei from synchronized HeLa cells has been studied in an effort to optimalize the system and characterize the product. The synthesis was highly dependent on the four deoxyribonucleoside triphosphates, ATP, and Mg2+. Optimum pH was about 7.8. The system was further stimulated by monovalent ions with NH4Cl and Tris-HCl (each 65 mM) being the most effective. The four ribonucleoside triphosphates and glycerol gave a slight but very reproducible and additive stimulation. Low concentrations of spermine and spermidine (0.2-1.5 X 10(-4) M) were also slightly stimulatory (10-15%) whereas higher concentrations were inhibitory. The reaction product was DNase sensitive, and banded at 1.699 g/ml in neutral CsCl together with bulk HeLa nuclear DNA. When studied by neutral CsCl and alkaline Cs2SO4 gradients, the incorporation of [3H]TTP was mainly (more than 85%) due to further elongation of strands initiated in vivo as evidenced by BrdUrd labeling.
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PMID:DNA synthesis in isolated HeLa cell nuclei. Optimalization of the system and characterization of the product. 24 74

The activity of DNase, purified from rat parotid saliva was studied as affected by 7 metal ions. It is found that Mg2+ activated the salivary DNase. Ca2+ and Ba2+ in concentrations exceeding 10(-3) M revealed the inhibitory action, while Zn2+ and Cu2+ under these conditions have an essential effect on the enzyme activity. Al3+ produced no significant effect on the DNase activity. The rat parotid DNase activity is the highest in imidazol and tris-HCl buffers (pH 7.2-7.4) in the presence of 2.5 . 10(-2) M of Mg2+.
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PMID:[Influence of ions on the activity of rat parotid DNase]. 66 27

Different systemic organs of fetal mice were continuously labelled with 5-3H-uridine during the organogenesis periods, and chased for various lengths of time after birth. In the autoradiographs made on paraffin-embedded sections of the organs taken after the chase for longer periods than 1 week, including a 12-months chase, specific labels were present exclusively in all the nuclei. The specific nuclear labels were resistant to RNase A or H digestion and to acid hydrolysis with 1 N HCl at 60 degrees C for 5 min, but were completely abolished by DNase digestion or prolonged acid hydrolysis for 10 min, the optimum condition for the Feulgen reaction to stain DNA. Electrophoretic analysis of the total nucleic acids extracted from the different organs chased for 3 or 12 months showed all the tritium radioactivity to be present in the DNA fraction before digestion with DNase or RNase A, and to be completely absent from the DNA fraction and shifted to the RNA fraction, or to be largely destroyed by degradation, after each digestion, respectively. By HPLC analysis of the total nucleic acid extract after further successive digestions with nuclease P1 and alkaline phosphatase into the constituent nucleotides, it was shown that all tritium activity was incorporated in uridine, without any detectable label in other nucleotides. By the simultaneous labeling of human peripheral lymphocytes at the late S-phase with 5-3H-uridine and BrdU, it was demonstrated that the autoradiographic labels, which, this time, were labile to RNase A digestion, were present in the G-bands of the spread chromosomes as identified by BrdU immunohistochemistry. The findings strongly indicate the presence of a novel class of nuclear RNA (nRNA). This type of RNA (a) may be localized in the nucleus in close association or hybridization with nuclear DNA, (b) have a life span as long as that of the cell, and (c) be duplicated in the late phase of DNA replication. The nRNA may play a fundamental role as gene repressor existing in the G-bands of metaphase chromosomes in the process of ontogeny and cytodifferentiation.
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PMID:A novel class of nuclear RNA (nRNA) with a long life span as a gene repressor candidate. 137 66

When isolated human fibroblast lysosomes are incubated with 4 microM [32P]phosphate at pH 7.0, orthophosphate is transported into lysosomes and is rapidly incorporated into low and high molecular weight products. We have characterized the high molecular weight (HMW) lysosomal material into which [32P]phosphate is incorporated and have found it to consist of long chains of inorganic polyphosphate based on the following observations. 1) greater than 97% of HMW 32P-lysosomal material is converted to [32P]orthophosphate when incubated with 1 N HCl for 20 min at 100 degrees C. 2) Incubation of HMW 32P-lysosomal material at pH 7.0 and 65 degrees C for 96 h results in the formation of [32P]trimetaphosphate, which is known to be produced only from linear chains of polyphosphate under these conditions. 3) HMW 32P-lysosomal material is resistant to degradation by proteinase K, ribonuclease, and deoxyribonuclease and extracts into the aqueous phase during phenol/chloroform extractions. 4) HMW 32P-lysosomal material displays heterogeneous mobility on polyacrylamide gels with most chains ranging in length from 100 to at least 600 phosphate residues. 5) HMW 32P-lysosomal material is partially hydrolyzed under alkaline conditions to yield a continuous ladder of polyphosphate species differing by one or several residues in length on polyacrylamide gels.
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PMID:Incorporation of [32P]orthophosphate into long chains of inorganic polyphosphate within lysosomes of human fibroblasts. 174 Apr 14

Several classes of specific progesterone receptor (PR) nuclear binding sites (acceptor sites) have previously been identified in avian oviduct chromatin on the basis of different binding affinities. Recently, two classes of acceptor proteins (AP) that are associated with these binding sites in the avian oviduct have been identified. These APs were termed receptor binding factors (RBF-1 and -2), and one (RBF-1) has been purified [Schuchard et al. (1991) Biochemistry 30, 4535-4542]. The RBF-1 is associated with the highest affinity class of sites in the intact chromatin, and the RBF-2 is associated with the second highest affinity class of sites. The PR binding sites and their associated RBF-2 protein remain with the residual chromatin fraction following extraction by 4 M Gdn-HCl. This Gdn-HCl-treated chromatin has been termed nucleoacidic protein (NAP). This paper describes the 200-fold enrichment of the native RBF-2 class of PR acceptor sites beginning with the DNase I digestion of NAP to obtain DNase-resistant fragment (NAPf) containing approximately 150 bp of DNA. The PR binding sites are further enriched by high-performance or fast protein liquid chromatography and chromatofocusing. Anti-RBF-1/RBF-2 protein antibodies identify antigens that coelute with the PR binding activity. Hybridization analysis of the DNAf from the enriched NAPf demonstrates sequence homologies with the nuclear matrix DNA as well as with genomic sequences of the rapid steroid responding nuclear protooncogenes c-myc and c-jun. However, comparative analyses of the whole genomic DNA with the nuclear matrix DNA indicate that the RBF-2 (NAPf) is largely nonnuclear matrix.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Enrichment of a second class of native acceptor sites for the avian oviduct progesterone receptor as intact chromatin fragments. 189 51


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