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)

The purification of ATP-dependent DNase from Bacillus cereus led to the isolation and characterization of a third DNA-dependent ATPase. The enzyme called ATPase III has been purified free of nuclease activity. None of the expected ATPases proved to be identical with ATP-dependent DNase-DNA-dependent ATPase. Separation of ATPase I, II and III and a DNase specific for single-stranded DNA from the same source excludes the possibility of ATP-dependent DNase being the action of a single enzyme molecule.
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PMID:A third DNA-dependent ATPase from Bacillus cereus free of ATP-dependent DNase activity. 613 44

Acid deoxyribonuclease (EC 3.1.4.6) (DNase) from young (16 days of incubation) and old (1.5 years) chick cerebral hemispheres was purified to apparent homogeneity. Throughout the purification schedule, the behavior of "young" and "old" enzymes was similar. However, the specific activity of the purified enzyme from old brain was only one-tenth that of young enzyme. Polyacrylamide gel electrophoresis of the purified acid DNase gave a single band. Antisera against both "young" and "old" enzyme were raised and double immunodiffusion experiments revealed cross-reaction of young antigen with old antiserum and vice versa, although precipitin bands with young antigen against young antiserum and old antigen against old antiserum were more sharp. Both young and old acid DNase preparations showed an apparent molecular weight of 62,000 and many other properties like heat stability, effect of various exogenous compounds like Hg2+, Zn2+, Mg2+, etc., were also similar. The old enzyme showed slightly higher Km and decreased Vmax compared with the young enzyme. Dansylation of N-terminal amino acids and their analysis following tryptic digestion of both "young" and "old" acid DNase revealed a similar pattern. Immunotitration experiments showed that the old enzyme requires more antiserum prepared against "young" enzyme to achieve 50% inactivation, thus pointing out the presence of completely or partially inactive molecules in "old" acid DNase preparation. Circular dichroism spectra of the enzyme preparations indicated that the "old" acid DNase molecules are more rigid and have more alpha-helical structure, compared with the "young" enzyme. From these data, it is suggested that the reduction in the specific activity of old acid DNase may be, apart from other possibilities, due to conformational changes in the enzyme molecules.
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PMID:Age-dependent conformational changes in acid deoxyribonuclease of chick brain. 619 64

The interaction of deoxyribonuclease I with muscle actin was studied with the aid of a pyrenyl derivative of the actin [Kouyama, T., & Mihashi, K. (1981) Eur. J. Biochem. 114, 33-38] that increases its quantum yield by an order of magnitude on polymerization. It is shown that this derivative copolymerizes with unlabeled G-actin in a random manner and will also bind to deoxyribonuclease with inhibition of enzymic activity. The derivative affords a highly sensitive means of following nucleated polymerization. Preincubation of F-actin with deoxyribonuclease at a concentration of 5% or less of that of total subunits causes inhibition of polymerization of additional G-actin onto the filaments. In red cell membranes that contain stabilized short filaments of actin such that the concentration of filament ends is large relative to monomers, complete inhibition of nucleated polymerization of G-actin is achieved by preincubation with deoxyribonuclease. The results indicate that binding of DNase occurs at the "plus" ends of the actin filaments. Competition with cytochalasin E, which is known to have a high affinity for the plus or preferentially growing ends of F-actin, can be observed. Whereas the activity of deoxyribonuclease in the 1:1 complex with G-actin is inhibited, the enzyme attached to the ends of filaments appears to be fully active. This causes a reduction in the inhibition of enzymic activity with increasing F-actin concentration, presumably by reason of a change in the partition of the enzyme between monomers and filament ends. The degree of inhibition increases with time, however, as the actin depolymerizes. Implications for measurements of actin monomer concentrations by the deoxyribonuclease assay procedure are considered.
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PMID:Investigation of the actin-deoxyribonuclease I interaction using a pyrene-conjugated actin derivative. 621 39

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

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

A deoxyribonuclease has been purified 570-fold from the 14-day-old chick embryos. The purified enzyme requires Mg2+ or Mn2+ ions for maximum activity. The optimum pH is 9.0 in 20 mM Tris-HCl buffer. Its isoelectric point is 6.7. NaCl and N-ethylmaleimide strongly inhibit the reaction. An apparent molecular weight of 45,000 is determined by sedimentation in a glycerol density gradient. The enzyme hydrolyzes denatured DNA 50 to 100 times more rapidly than duplex DNA. RNA and synthetic polyribonucleotides are not substrate for the enzyme. DNase A catalyzes the endonucleolytic and exonucleolytic cleavages of single-stranded DNA. The enzyme produces DNA fragments having 70 to 100 nucleotides long at early time of reaction and then degrades these DNA fragments to acid-soluble materials, of which more than 70% is mononucleotides. In the exonucleolytic attack, the enzyme initiates hydrolysis of a single-stranded DNA from 5' to 3' direction. Chick embryo DNA-binding protein gives an intensive effect on the DNase A reaction by inhibiting the endonuclease activity rather than exonuclease activity under the standard assay conditions.
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PMID:Deoxyribonuclease A of chick embryo. Partial purification and characterization of the enzyme. 682 17

The immunologic responses to streptolysin O and streptococcal deoxyribonuclease B were evaluated in children with group A streptococci recovered from the upper respiratory tract to re-examine the hypothesis that a limited capacity to respond to group A streptococcal infection may explain the rare occurrence of acute rheumatic fever in very young children. ASO and anti-DNase B titers were determined on serial bleedings from a total of 301 individuals (52 less than or equal to 3 years; 249 older than 3 years). Very young children with group A streptococcal upper respiratory tract infections had an immunologic response to SO greater than the response in older children as reflected by the magnitude of the antibody rise, and comparable to the ASO response in older children as measured by the percentage showing a significant titer rise. Similar analyses of the anti-DNase B responses showed the response in young children to be comparable to those of the older group. Clinical manifestations of group A streptococcal upper respiratory tract infection in very young children differ from those observed in older children and have not changed significantly in the past several decades. These data suggest that the infrequent occurrence of acute rheumatic fever in very young children is not due to a difference in antibody response to streptolysin O or streptococcal DNase B.
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PMID:The immunologic response to group A streptococcal upper respiratory tract infections in very young children. 698 55

A deoxyribonuclease activity with specificity towards single-stranded DNA has been purified approximately four hundred-fold from KB cells, by chromatography on DEAE-cellulose, phosphocellulose and hydroxylapatite. The last step of the purification results in separation of the enzyme from a DNase activity which has been described previously (Wang, E.C., Furth, J.J. and Rose, J.A., (1978) Biochemistry 17: 544-549). The properties of the new DNase activity are significantly different from those of the enzymes which have previously been identified in these cells. The activity sediments at approximately 7.5S in a glycerol gradient. The DNase activity is optimal at pHs between 6.0 and 6.5. It cleaves DNA endonucleolytically and hydrolyzes single-stranded DNA at about 11 times the rate of double-stranded DNA and at twice the rate of Poly (dA). The activity is moderately sensitive to inhibition by N-ethylmaleimide and is inhibited 80% by 50 mM NaCl. It is stimulated twenty-fold by Mn++ at an optimal concentration of approximately 0.7 mM. It is stimulated by a lesser extent by Mg++, but not by Ca++.
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PMID:Purification and properties of a new DNase activity from KB cells. 732 24

Chronic pulmonary infection is the major cause of morbidity and mortality in cystic fibrosis (CF). Recombinant human deoxyribonuclease (rhDNase) in vitro has been shown to dramatically reduce the viscoelasticity of the sputum from CF patients. Phase II and III clinical trials have shown the drug to be safe, and that patients with a forced vital capacity (FVC) of > 40% predicted show an improvement in pulmonary function when receiving rhDNase. The current study evaluates the safety and efficacy of rhDNase in the most severly ill CF patients (FVC < 40% predicted). A double-blind, randomized, placebo-controlled trial in which patients received either 2.5 mg rhDNase twice daily or placebo for a period of 14 days followed by a 6 month open extension period (OEP) is reported. Seventy patients were recruited for the double-blind study, and 64 entered the OEP of whom 38 completed. During the OEP, all patients received 2.5 mg rhDNase twice daily. In both the double-blind period and the OEP the drug appeared to be safe. During the double-blind study, forced expiratory volume in one second (FEV1) and FVC improved in both groups but there was no statistically significant difference between the groups. In the OEP, there was mean improvement in percentage predicted FEV1 and FVC, 9 and 18%, respectively, for all patients participating. In conclusion, DNase is safe when administered in conjunction with a rigorous regimen of chest physiotherapy to severely ill patients (FVC < 40% predicted) with CF. The double-blind, 14 day study showed no significant improvement in pulmonary function but some patients may have improved after longer administration of rhDNase.
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PMID:Recombinant human DNase I in cystic fibrosis patients with severe pulmonary disease: a short-term, double-blind study followed by six months open-label treatment. 758 82


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