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:3.1.21.3 (deoxyribonuclease)
1,528 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ribosomal preparations obtained from Salmonella typhimurium by differential centrifugation and sodium dodecyl sulfate (SDS) treatment of the bacillary lysate were found to be immunogenic in F(1) hybrid (C(3)H/HeJ x DBA/2J) and albino Swiss mice, as determined by progressive host survival. The immunity obtained was independent of the need for adjuvant and dependent on the dosage of immunogen given. Immunizations with the ribosomal preparations induced an immune response comparable to that obtained by vaccination with living organisms and significantly greater than that obtained by immunization with heat-killed salmonellae, purified lipopolysaccharide, or crude and SDS-treated endotoxin preparations. No effect on the immunogenicity of the ribosomal fraction was observed by enzymatic treatment with trypsin, Pronase, deoxyribonuclease, and pancreatic ribonuclease. Linear sucrose density gradient resolution of the preparations showed that the immunogenicity of the ribosomal fraction was not unique to any one of its subcomponents. Ethyl alcohol-precipitated, crude ribonucleic acid preparations obtained from the ribosomal and sucrose density-resolved ribosomal preparations were found to induce an immune response comparable to that obtained by immunization with the entire ribosomal fraction. Dialysis in doubly distilled demineralized water slightly reduced the immunogenicity of the preparation; however, comparable dialysis in 10(-4)m MgCl(2)-phosphate buffer did not. Chemical assays of the preparations found to be immunogenic were performed.
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PMID:Isolation and partial characterization of an immunogenic moiety obtained from Salmonella typhimurium. 489 82

Group H streptococci (strain Challis) which are competent for transformation release a bacteriocin into liquid medium which is bacteriocidal for another group H streptococcus (strain Wicky). The streptocin (STH(1)) is resistant to treatment with deoxyribonuclease and ribonuclease but is sensitive to trypsin, phospholipase C, and alkaline phosphatase. Such enzyme sensitivity experiments indicate that the bacteriocin may be a complex molecule (protein and lipid) containing phosphate groups essential for activity. STH(1), which is readily distinguishable from competence factor and bacteriophage activity, appears to have no role in the initiation of the competent state in strain Wicky. The presence of this factor in Challis culture supernatant fluids indicates that a reevaluation of earlier studies performed with the Challis-Wicky transformation system may be necessary.
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PMID:Bacteriocin production by transformable group H streptococci. 508 61

Pasteurella pestis, harvested after 24 to 30 hr of growth in a casein hydrolysate medium at 26 C, was resuspended and shaken in 3% lactose-0.1 m phosphate buffer for 4 hr at the same temperature. Certain characteristics of these starved cells were compared with those of control cells. No differences in the amounts of cellular carbohydrate or lipid were detected. The concentrations of the principal free amino acids were greater in the shaken cells, except that they contained no measureable arginine, and the normally large pools of intracellular tricarboxylic acid cycle intermediates were reduced. Greater viable-cell counts resulted with the cells that were shaken in lactose buffer than with the control cells when each was incubated at 5 C for several weeks. However, the reduced viabilities were apparent losses caused by the formation of aggregates of cells. The clumping of cells was caused by the polymerization of extracellular nucleic acids, principally deoxyribonucleic acid, that were excreted by the cells. Cell clumping could be partially prevented by prior shaking of the suspended cells, which removed some of the deleterious material, or by the action of crystalline deoxyribonuclease.
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PMID:Biochemical and physical changes in shaken suspensions of Pasteurella pestis. 533 54

1. The pH optimum, ionic requirement and heat-stability of a purified liver nuclease have been examined with RNA and denatured DNA as substrates. 2. The enzyme attacked DNA and RNA in an endonucleolytic manner, forming oligonucleotides terminated by 5'-phosphate groups. No clear specificity was found with respect to the bases at the site of cleavage. 3. Comparison of the results obtained with RNA and denatured DNA as substrates suggests that the ribonuclease and deoxyribonuclease activities are associated with the same protein.
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PMID:Properties of a purified rat-liver nuclease. 591 29

Auletta, Angela E. (Catholic University, Washington, D.C.), and E. R. Kennedy. Deoxyribonucleic acid base composition of some members of the Micrococcaceae. J. Bacteriol. 92:28-34. 1966.-Thirty-seven strains from the genera Micrococcus, Staphylococcus, Gaffkya, and Sarcina were examined for deoxyribonucleic acid base composition and biochemical activity. Organisms were tested for production of catalase, coagulase, deoxyribonuclease, oxidase, phosphatase, hydrogen sulfide, indole, and acetoin; nitrate reduction; gelatin, starch, and urea hydrolysis; citrate and ammonium phosphate utilization; NaCl tolerance; growth at 10 and 45 C, and growth in litmus milk. They were tested for production of acid from dextrose and mannitol under anaerobic conditions, and for aerobic production of acid from dextrose, mannitol, lactose, sucrose, raffinose, maltose, xylose, and glycerol. Organisms could be divided into two groups on the basis of guanine-cytosine (GC) content. Group I had an average GC content of 32%, and included all organisms which produced acid from dextrose. Group II had an average GC content of 62%, and included those organisms incapable of producing acid from dextrose under anaerobic conditions. Sarcina ureae had a GC content of 43%.
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PMID:Deoxyribonucleic acid base composition of some members of the Micrococcaceae. 594 Dec 82

Infectious entities, extractable, with phosphate buffer, from tissue infected with potato spindle tuber virus and inciting symptoms on tomato that are typical of this virus, have properties incompatible with those of conventional virus particles. The infectious particles sediment in sucrose density gradients at approximately the same rate as particles with a sedimentation coefficient of 10S, are insensitive to treatment with organic solvents, and can be concentrated by ethanol precipitation. Treatment with phenol changes neither their infectivity nor their sedimentation properties. Infectivity is insensitive to deoxyribonuclease, but at low ionic strength it is sensitive to ribonuclease. At high ionic strength, infectivity partially survives incubation with ribonuclease. These properties, as well as elution patterns from columns of methylated serum albumin, suggest that the extractable infectious agent may be a double-stranded RNA.
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PMID:Potato spindle tuber virus: a plant virus with properties of a free nucleic acid. 606 89

Purpura was grossly observable in albino mice 6 to 8 h after the intraperitoneal injection of sterile, deoxyribonuclease-treated, cell-free extracts prepared by sodium deoxycholate-induced lysis, sonic disruption, Parr bomb treatment, autolysis without sodium deoxycholate, or alternate freezing and thawing of washed suspensions of Streptococcus pneumoniae type I. Cell-free extracts obtained from sonically disrupted, heat-killed cells (100 degrees C for 20 min) did not contain purpurogenic activity. The reaction was maximal at approximately 24 h postinjection, started to fade slowly after 24 to 48 h, and usually was not grossly observable by 4 to 6 days postinjection. The purpura-producing principle (PPP) in the cell-free extract was purified by sequential ammonium sulfate precipitation, protamine sulfate precipitation, Sepharose 6B gel filtration, wheat germ lectin-Sepharose 6MB affinity chromatography, ribonuclease and trypsin treatment, and a second Sepharose 6B gel filtration step. The final preparation (i) contained glucosamine (5.6%), muramic acid (8.0%), neutral carbohydrate (12.8%), phosphate (8.0%), orcinol-reactive material (6.0%), and Lowry-reactive material (1.6%), and (ii) was free of detectable amounts of deoxyribonucleic acid, capsular polysaccharide, neuraminidase, cytolysin, and hyaluronidase. The isoelectric point and molecular size of the PPP were approximately pI 3.0 and several million daltons, respectively, and the activity remained in the supernatant fluid after centrifugation for 1 day at 105,000 x g. PPP activity was destroyed by incubation with egg white lysozyme and sodium metaperiodate but was resistant to trypsin, pronase, alpha-amylase, deoxyribonuclease, ribonuclease, alkaline phosphatase, pancreatic lipase, 7% trichloroacetic acid, 6 M urea, autoclaving (121 degrees C) for 30 min, and mild acid and alkali exposure. Our observations indicate that the PPP requires intact beta-1,4-glucosidic linkages for activity and support the working hypothesis that activity is associated with pneumococcal peptidoglycan solubilized by the bacterium's autolysin.
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PMID:Characterization of pneumococcal purpura-producing principle. 624 53

Studies on the specificity of the ATP-dependent DNase of Bacillus subtilis 168, carried out with pure enzyme at the optimal conditions for its action, have shown that the substrate is double-stranded linear DNA. Linear single-stranded DNA (separated strands of B. subtilis DNA and linear phage fd DNA) is not attacked, neither are there any circular forms (supercoiled or nicked simian virus 40 and circular single-stranded fd DNAs). The double-stranded DNA can be completely hydrolysed, the limit products being, almost exclusively, mononucleotides. The presence of terminal phosphate residues in the substrate (either at the 3' or the 5' end) is not necessary for enzyme action. This DNase appears therefore to be an exonuclease processively liberating mononucleotides from both strands of the native linear DNA. ATP (indispensable for the DNase reaction) is also hydrolysed by the enzyme, to ADP and inorganic orthophosphate (Pi) in the presence of DNA. The apparent Km for ATP, in the ATPase reaction, is 0.15 mM. At high ATP concentrations, which inhibit the DNase activity, there is activation of the ATPase reaction. Three molecules of ATP are consumed for each DNA phosphodiester bond split, at optimal conditions for DNase activity.
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PMID:Substrate specificity and adenosine triphosphatase activity of the ATP-dependent deoxyribonuclease of Bacillus subtilis. 626 14

Bacillus laterosporus ATP-dependent deoxyribonuclease has been found to be inhibited by pyridoxal 5'-phosphate. The inhibition is specific for pyridoxal 5'-phosphate and pyridoxal which are required in relatively high concentrations. Pyridoxamine 5'-phosphate, pyridoxamine, and pyridoxine are ineffective. The inhibition is reversed by dilution or dialysis but can be changed to an irreversible inactivation by reduction of the enzyme . pyridoxal 5'-phosphate complex with sodium borohydride. The compound is a competitive inhibitor with respect to DNA but not ATP. Moreover, the presence of DNA substrate protects the enzyme against this inactivation but the presence of ATP shows no effect. The reduced enzyme . pyridoxal 5'-phosphate complex displays a new absorption maximum at 325 nm and a fluorescence emission at 390-400 nm when excited at 325 nm which are characteristic for epsilon-N-(phosphopyridoxyl)lysine. Thus, B. laterosporus DNase appears to have an essential lysine residue at the DNA binding site of the enzyme, and the enzyme possess two different active sites, a DNA binding site and an ATP binding site.
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PMID:Inhibitory effect of pyridoxal 5'-phosphate on the DNA binding site of ATP-dependent deoxyribonuclease from Bacillus laterosporus. 626 33

Escherichia coli endonuclease VI is a deoxyribonuclease specific for AP (apurinic or apyrimidinic) sites; it cleaves the phosphodiester bond immediately neighbouring the AP site on its 5' side leaving 3'-hydroxyl and 5'-phosphate ends. DNA with AP sites can be repaired in vitro with endonuclease VI, DNA polymerase I and ligase; the repair mechanism is described. E. coli has other AP endonucleases; some of them are not specific for AP sites and some of them cut 3' to the AP sites. Most of the rat liver AP endonuclease activity is in chromatin. Some is however found in other cell compartments and it has been speculated that these enzymes might be precursors of the chromatin enzyme. The chromatin AP endonuclease is specific for AP sites; it cuts 5' to the AP site. DNA with AP sites can be repaired in vitro with enzymes purified from chromatin; AP endonuclease, 5'-3 exonuclease, DNA polymerase beta and ligase.
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PMID:Repair of AP sites in DNA. 681 9


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