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 prodcedure was developed for the purification of the ATP-dependent deoxyribonuclease of Bacillus subtilis 168. It comprises ammonium sulphate fractionation, Sephadex gel filtration, DEAE-cellulose chromatography and gel electrophoresis on a discontinuous polyacrylamide gradient. The enzyme has been obtained in a homogeneous state. Its molecular weight was estimated to be 270000 by disc electrophoresis. Dodecylsulfate-polyacrylamide gel electrophoresis showed the presence of five nonidentical subunits of the following molecular weights: 81000, 70000, 62000, 52500 and 42500. These values give 308000 as the molecular weight of the native enzyme. The pH optimum of the purified enzyme is 9.6. The optimal concentrations of Mg2+ and ATP for exonuclease activity on native B. subtilis DNA were determined. ATP-requirement for hydrolysis of single-stranded DNA is less strigent. The enzyme also possesses high DNA-dependent ATPase activity. The purification procedure was applied to extracts of a mutant devoid of activity for this enzyme (strain GSY 1290). A protein was isolated which is very similar to the active DNAase as regards electrophoretic mobility, reaction with specific antisera and size of four of the subunits. One subunit is missing (Mr 70000) and is replaced by a smaller polypeptide (Mr 565000). The latter results suggest that the mutant is affected in the genetic locus coding for the 70000-Mr subunit.
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PMID:Isolation, subunit structure and properties of the ATP-dependent deoxyribonuclease of Bacillus subtilis. State of the protein in a mutant devoid of activity. 1 60

The activity of ATPase was studied in highly purified rat liver and thymus cell nuclei, HCO3-, CO3(2-) and SO3(2-) stimulated nuclear ATPase in 1.5--2 times. HSO3- did not affect the enzyme activity, and NO3-, J-, ClO4-,F- and SCN- inhibited it. Bicarbonate increased V and decreased Ka for ATP. SCN- inhibited HCO3--ATPase activity non-competitively with respect to HCO3-. Mg2+-ATPase activity did not depend on pH, and HCO3-component of the activity was decreased under alkaline pH. Mg2+, Mn2+ and Co2+ increased the initial ATPase activity and helped its stimulation with HCO3-. Ba2+, Ni2+ and Zn2+ inhibited the ATPase activity, and Ca2+ did not affect it, Nuclear ATPase is sensitive to 2,4-dinitrophenol and DNAase. It is suggested that cell nuclei have their own H+-ATPase differing for some characteristics from mitochondrial H+-ATPase.
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PMID:[Investigation of adenosinetriphosphatase activity of rat liver and thymus cell nuclei]. 3 23

An adenosine triphosphate-stimulated deoxyribonuclease was purified to about 4200 fold from Bacillus cereus. The enzyme activity of the crude extract increased by a factor of about 5 after dialysis. One of the low molecular weight inhibitors of the crude extract was found to be inorganic phosphate. During enzyme purification two nucleases were identified. One of them was specific to denatured DNA and the other one degraded both denatured DNA and native DNA. The activity towards native DNA could be increased several times by ATP. Through all steps of purification the ATP-independent DNase always accompanied the ATP-dependent one and the ratio of their activity was found to be constant. The ATP-dependent DNase also possessed ATPase activity stimulated both by native and denatured DNA. The fact that ATPase was stimulated by DNA and went together with ATP-dependent DNase during purification suggests that these functions belong to the same enzyme complex. Maximal activity of ATPase had broader pH, Mg2+ and ATP concentration ranges than that of DNase. Cooperation of the two functions may be limited only to a narrow range of ATP concentration. Km for ATPase was 1.6x10-4 M ATP.
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PMID:An adenosine triphosphate dependent deoxyribonuclease with adenosine triphosphatase, activity from Bacillus cereus. 4 71

DNA polymerase was purified from Drosophila melanogaster embryos by a combination of phosphocellulose adsorption, Sepharose 6B gel filtration, and DEAE-cellulose chromatography. Three enzyme forms, designated enzymes I, II, and III, were separated by differential elution from DEAE-cellulose and were further purified by glycerol gradient centrifugation. Purification was monitored with two synthetic primer-templates, poly(dA) . (dT)-16 and poly(rA) . (dT)-16. At the final step of purification, enzymes I, II, and III were purified approximately 1700-fold, 2000-fold and 1000-fold, respectively, on the basis of their activities with poly(dA) . (dT)-16. The DNA polymerase eluted heterogeneously as anomalously high-molecular-weight molecules from Sepharose 6B gel filtration columns. On DEAE-cellulose chromatography enzymes I and II eluted as distinct peaks and enzyme III eluted heterogeneously. On glycerol velocity gradients enzyme I sedimented at 5.5-7.3 S, enzyme II sedimented at 7.3-8.3 S, and enzyme III sedimented at 7.3-9.0 S. All enzymes were active with both synthetic primer-templates, except the 9.0 S component of enzyme III, which was inactive with poly(rA) . (dT)-16. Non-denaturing polyacrylamide gel electrophoresis did not separate poly(dA) . (dT)-16 activity from poly(rA) . (dT)-16 activity. The DNA polymerase preferred poly(dA) . (dT)-16 (with Mg2+) as a primer-template, although it was also active with poly(rA) . (dT)-16 (with Mn2+), and it preferred activated calf thymus DNA to native or heat-denatured calf thymus DNA. All three primer-template activities were inhibited by N-ethylmaleimide. Enzyme activity with activated DNA and poly(dA) . (dT)-16 was inhibited by K+ and activity with poly(rA) . (dT)-16 was stimulated by K+ and by spermidine. The optimum pH for enzyme activity with the synthetic primer-templates was 8.5. The DNA polymerases did not exhibit deoxyribonuclease or ATPase activities. The results of this study suggest that the forms of DNA polymerase from Drosophila embryos have physical properties similar to those of DNA polymerase-alpha and enzymatic properties similar to those of all three vertebrate DNA polymerases.
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PMID:Three forms of DNA polymerase from Drosophila melanogaster embryos. Purification and properties. 9 4

Infection of Escherichia coli with bacteriophage T7 results in an inhibition of the host exonuclease V (recB, C DNase) activity. This inhibition is not observed when cells are infected in the presence of chloramphenicol or with a gene 1 mutant. The protein responsible for the inhibition of exonuclease V has been partially purified from T7-infected cells. The protein which does not possess nuclease or ATPase activity can inhibit all nucleolytic activities associated with exonuclease V. The protein does not, however, inhibit the DNA-dependent ATPase activity associated with exonuclease V. The inhibitory protein has a molecular weight of about 12,000, as determined from sedimentation analysis in glycerol gradients.
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PMID:Partial purification and properties of a bacteriophage T7 inhibitor of the host exonuclease V activity. 12 51

Infection by bacteriophage T4 has previously been shown to cause a rapid inhibition of the host recBC DNase, an ATP-dependent DNase that is required for genetic recombination in Escherichia coli. We report here the partial purification of a protein ("T4 rec inhibitor") from extracts of T4-infected cells and some characteristics of the in vitro inhibition reaction with purified inhibitor and recBC nuclease. This inhibitory activity could not be purified from extracts of uninfected E. coli. Both the ATP-dependent exonuclease and DNA-dependent ATPase activities of recBC DNase are inhibited by T4 rec inhibitor. Experiments suggest that the inhibitor interacts with the nuclease in a stoichiometric manner. The biological significance of this inhibition is discussed with respect to control reactions in phage-infected cells.
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PMID:Postinfection control by bacteriophage T4 of Escherichia coli recBC nuclease activity. 13 May 1

The combination effects of chlorpromazine (CPZ) and periphenazine (PPZ) with beta-lactam antibiotics (ampicillin, carbenicillin, cefazolin) and nalidixic acid group compounds (nalidixic acid, piromidic acid and pipemidic acid) have been estimated to be synergistic by the filter paper strip-agar diffusion method (Dye's method) with Escherichia coli and Pseudomonas aeruginosa as test organisms. The observed synergism might be associated with their inhibition of various enzymes including ATPase and DNAase as well as with their specific binding to DNA. Similar synergistic effects of CPZ and PPZ have been shown by the broth dilution method. Based on these findings, it seems to be a fascinating project to devise a new phenothiazine drug without influence in mental disease that will have a greater measure of synergistic effect when combined with the above-studied antibacterial agents.
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PMID:Synergistic effects of chlorpromazine and perphenazine on several chemotherapeutic agents. I. General profile of the effects measured by the filter paper strip-agar diffusion method with Escherichia coli and Pseudomonas aeruginosa. 14 36

A DNA-unwinding protein has been purified from regenerating rat liver cytosol to apparent homogeneity. The protein is present in about 10(6) copies per cell. It is a tetramer, composed of 25,000-dalton subunits which does not exhibit enzymatic activity for ATPase, DNA polymerase, or DNase. The protein is able to unwind the double helix of poly[d(A-T)], depressing the melting point of this synthetic polymer by about 40 degrees. It also binds to supercoiled SV40 DNA, probably by melting A-T-rich regions in the genome. The fully saturated complex of protein and SV40 DNA sediments at 30 S. Homologous DNA polymerases-alpha and -beta are stimulated by the protein at a different level depending on the templates used. This result argues in favor of the intervention of the unwinding protein in replication processes.
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PMID:A deoxyribonucleic acid unwinding protein isolated from regenerating rat liver. Physical and functional properties. 20 98

The peripheral membrane protein fraction released by washing Acholeplasma laidlawii membranes with low-ionic strength buffers contained about 50% of the total membrane-bound ribonuclease and deoxyribonuclease activities. The ATPase, NADH oxidase and p-nitrophenylphosphatase activities remained bound to the membrane even when EDTA was added to the wash fluids, and thus appear to belong to the integral membrane protein group. Serving as a marker for peripheral membrane proteins, the membrane-bound ribonuclease activity was solubilized by bile salts much more effectively than the integral membrane-bound enzymes. On the other hand, the solubilized ribonuclease showed a much lower capacity to reaggregate with other solubilized membrane components to membranous structures. Yet, most of the ribonuclease molecules which were bound to the reaggregated membranes could not be released by low-ionic strength buffer. The reaggregated membranes differed from the native membranes in the absence of particles on their fracture faces obtained by freeze cleaving, and by their much higher labeling by the [125-I]lactoperoxidase iodination system. These results suggest that most of the proteins are exposed on the reaggregated membrane surfaces, with very little, if any, protein embedded in its lipid bilayer core. Enzyme disposition in the A. laidlawii membrane was studied by comparing the activity of isolated membranes with that of membranes of intact cells after treatment with pronase or with an antiserum to membranes. The data indicate the asymmetrical disposition of these activities, the ATPase and NADH oxidase being localized on the inner membrane surface, while the nucleases are exposed on the external membrane surface.
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PMID:Characterization of the mycoplasma membrane proteins. V. Release and localization of membrane-bound enzymes in Acholeplasma laidlawii. 23 52

Chemically tritiated actin from rabbit skeletal muscle was used to investigate the association of G-actin with the red cell membrane. The tritiated actin was shown to be identical to unmodified actin in its ability to polymerize and to activate heavy meromyosin ATPase. Using sealed and unsealed red cell ghosts we have shown that G-actin binds to the cytoplasmic but not the extracellular membrane surface of ghosts. Inside-out vesicles which have been stripped of endogenous actin and spectrin by low-ionic-strength incubation bind little G-actin. However, when a crude spectrin extract containing primarily spectrin, actin, and band 4.1 is added back to stripped vesicles, subsequent binding of G-actin can be increased up to 40-fold. Further, this crude spectrin extract can compete for and abolish G-actin binding to unsealed ghosts. Actin binding to ghosts increases linearly with added G-actin and requires the presence of magnesium. In addition, actin binding is inhibited by cytochalasin B and DNAase I. Negative staining reveals an abundance of actin filaments formed when G-actin is added to reconstituted inside-out vesicles but none when it is added to unreconstituted vesicles. These observations indicate that added G-actin binds to the red cell membrane via filament formation nucleated by some membrane component at the cytoplasmic surface.
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PMID:Actin--membrane interactions: association of G-actin with the red cell membrane. 73 9


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