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 deoxyribonuclease (DNase) was isolated from viscera of the cold-adapted marine bivalve Icelandic scallop. The 42 kDa DNase was shown to be a single polypeptide which catalyses DNA hydrolysis in the absence of divalent cations. The isolated enzyme showed maximal activity at pH 6 and no activity above pH 7.2 against native DNA. The scallop DNase was slightly more susceptible to heat denaturation than porcine DNase II and makes double-strand breaks in circular DNA substrate as the porcine enzyme. The N-terminal sequence of the scallop DNase was shown to be closely similar to DNase II (EC 3.1.22.1) proteins from other organisms. The scallop DNase is in addition to plancitoxin I from A. planci, the only DNase II enzyme isolated from marine invertebrates.
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PMID:Deoxyribonuclease II from the Icelandic scallop (Chlamys islandica): isolation and partial characterization. 1642 84

Acid endonucleases of the deoxyribonuclease II (DNase II, EC 3.1.22.1) family have been implicated in the degradation of DNA from apoptotic cell corpses formed in the process of normal mammalian development. Although a predicted DNase II has been detected in the chicken through expressed sequence tag (EST) analysis, to date no homolog of these important enzymes has been identified in vivo in any avian species. Here we report the cloning and expression of DNase II from the chicken, Gallus gallus. When expressed, the 363 amino acid glycoprotein is observed to be approximately 45 kDa in size and to exhibit DNA hydrolytic activity at pH 5 consistent with DNase II in other species. Furthermore, chicken DNase II sequence is compared with an identified partial sequence from the zebra finch, Taeniopygia guttata, as well as the previously identified homologs found in the fowlpox and canarypox viruses and the previously cloned mammalian DNases II. Through analysis of its amino acid sequence, comparative gene structure, and conserved synteny, chicken DNase II appears to represent a member of the DNase IIbeta subfamily and the apparent lack of a DNase IIalpha homolog in the chicken has important evolutionary implications for the study of this gene family.
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PMID:Cloning and expression of deoxyribonuclease II from chicken. 1650 43

DNase II is an acid endonuclease that is involved in the degradation of exogenous DNA and is important for DNA fragmentation and degradation during cell death. In an effort to understand its catalytic mechanism, we constructed plasmids encoding nine different histidine (H)-to-leucine (L) mutants for porcine DNase II and examined the enzyme properties of the expressed mutant proteins. Of the mutants, all but H132L were secreted into the medium of expressing cells. Six of the mutated DNase II proteins (H41L, H109L, H206L, H207L, H274L and H322L) showed enzyme activity, whereas the H115L, H132L and H297L mutants exhibited very little activity. The H115L and H297L mutants were found to undergo correct protein folding, but were inactive. To further examine these mutants, we expressed H115A and H297A DNase II mutants; these mutants were inactive, but their DNase activities could be rescued with imidazole, indicating that His115 and His297 are likely to function as a general acid and a general base respectively in the catalytic centre of the enzyme. In contrast with the secreted mutants, the H132L mutant protein was found in cell lysates within 16 h after transfection. This protein was inactive, improperly folded and was drastically degraded via the proteosomal pathway after 24 h. The polypeptide of another substitution for His132 with lysine resulted in the misfolded form being retained in endoplasmic reticulum.
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PMID:Identification of three crucial histidine residues (His115, His132 and His297) in porcine deoxyribonuclease II. 1673 90

Apoptosis is characterized by cell shrinkage, nuclear condensation and internucleosomal DNA cleavage. Besides the central role of caspases and other proteases, cell death triggers DNA degradation so that DNases have an active role in apoptotic cell death. The best-characterized apoptotic DNase is CAD, a neutral Mg-dependent endonuclease. Its activity is regulated by its inhibitor, ICAD, which is cleaved by caspases. Other neutral DNases have been shown to cleave nuclear DNA in apoptotic conditions: endonuclease G, GADD. In cells, the cytosolic pH is maintained to 7.2, mostly due to the activity of the Na(+)/H(+) exchanger. In many apoptotic conditions, a decrease of the intracellular pH has been shown. This decrease may activate different acid DNases, mostly when pH decreases below 6.5. Three acidic DNases II are so far known: DNase II alpha, DNase II beta and L-DNase II, a DNase II, derived from the serpin LEI (Leukocyte Elastase Inhibitor). Their activation during cell death is discussed in this review.
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PMID:Acid DNases and their interest among apoptotic endonucleases. 1698 34

We have developed two microtiter plate assays to quantify the deoxyribonuclease activity in biological fluids. Both assays are based on hydrolysis of biotinylated and fluorescein-labeled DNA substrates, with subsequent immunochemical detection of non-digested DNA. The assay based on hydrolysis of 974 bp PCR product labeled with biotinylated forward and fluorescein-labeled reverse primers is more sensitive (0.05 U/ml) and convenient for quantifying the DNase activity in biological fluids than the assay based on hydrolysis of double-labeled 20 bp oligonucleotide. The DNase activity in urine and blood plasma of healthy donors was measured using the PCR product-based assay. Urine samples revealed greater activity, 1.49+/-1.41 U/ml; blood plasma DNase I-like activity was 0.36+/-0.20 U/ml. DNase II-like activity was not detected in the plasma samples. The data obtained confirm that DNase I-like enzymes are responsible for the majority of deoxyribonuclease activity in blood plasma.
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PMID:Immunochemical assay for deoxyribonuclease activity in body fluids. 1761 45

Bovine pancreatic deoxyribonuclease I (bpDNase I) contains four cysteine residues forming two disulfide bonds. Though there are no free sulfhydryl groups, incubation of bpDNase I with 2-nitro-5-thiosulfobenzoic acid (NTSB) in the presence of Ca(2+) or Mg(2+) at pH 7.5 results in inactivation of the enzyme. Amino acid analysis shows that NTSB-treated bpDNase I still contains all 4 half-cystine residues. The only amino acid residues having reduced values are threonine and serine, indicating that these may be the reaction sites for NTSB. Plasmid scission assay and circular dichroism analysis reveal the structural integrity of the inactivated enzyme. Treatment of bpDNase I with NTSB does not result in fragmentation, as demonstrated by SDS-PAGE analysis. NTSB binds bpDNase I through covalent modification, since dialysis and gel filtration can not reverse the inactivation reaction. However, after dilution into an acid buffer of pH 4.7, the inactivated enzyme regains about 40% of its initial activity, suggesting a reversible inactivation by acid treatment. NTSB does not inactivate DNase II, ribonuclease, chymotrypsin and lysozyme, while it effectively inactivates rat parotid DNase I. These results strongly suggest that NTSB can be considered as a novel inhibitor specific for DNase I.
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PMID:2-nitro-5-thiosulfobenzoic acid as a novel inhibitor specific for deoxyribonuclease I. 1829 70

DNA degradation is one of the hallmarks of programmed cell death, or apoptosis. Recent analyses of this process revealed that apoptotic DNA degradation is mediated by two independent mechanisms. First, the caspase-activated DNase (CAD) cell autonomously cleaves DNA into nucleosomal units in dying cells. Then, after the apoptotic cells are engulfed by macrophages, the fragmented DNA is further degraded by DNase II in the lysosomes of the macrophages. This chapter describes assay procedures for CAD and DNase II. It includes biochemical methods for quantifying DNase activity and cell culture systems to follow cell-autonomous and noncell-autonomous DNA degradation. These techniques are useful for studying DNases that are involved in programmed cell death and for following the engulfment of apoptotic cells by phagocytes.
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PMID:Nucleases in programmed cell death. 1866 75

The serum of patients with many autoimmune (AI) diseases contains small fractions of antibodies possessing both DNase and RNase activities. It was shown that immunization of rabbits with DNA, RNA, DNase I and RNase leads to production of antibodies with DNase and RNase activities. It is not known whether anti-idiotypic antibodies against DNase II can possess DNase or RNase activity. Electrophoretically and immunologically homogeneous polyclonal IgGs (pIgGs) from the sera of rabbits immunized with DNase II were obtained by sequential chromatography of the serum proteins on Protein A-Sepharose and gel filtration. It was shown for the first time that immunization of healthy rabbits with bovine DNase II produces IgGs with intrinsic DNase and RNase activities. IgGs from rabbits immunized with BSA or non-immunized animals were catalytically inactive. It was shown that approximately 10% of the total IgG DNase and RNase activities belong to anti-idiotypic antibodies to DNase II ( approximately 0.1% of total pIgGs), while 90% of the activities did not interact with Sepharose bearing antibodies against DNase II and might be antibodies to nucleic acids bound to DNase II. Affinity chromatography on DNA-cellulose using elution of antibodies with different concentration of NaCl and an acidic buffer separated catalytic IgGs into five antibody subfractions, three of which hydrolyzed RNA faster than DNA while two subfractions demonstrated only DNase activity. Our data suggest that a fraction of abzymes from AI patients hydrolyzing both DNA and RNA can contain subfraction of antibodies against DNase II.
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PMID:Immunization of rabbits with DNase II leads to formation of polyclonal antibodies with DNase and RNase activities. 1920 53

Nanomaterials are finding increasing use in industrial production and daily life. However, human exposure to them may cause health risks. Nano-SiO(2) was selected as a representative nanomaterial and its potential effects were investigated in terms of its interactions with cytochrome c (cyt c), deoxyribonuclease (DNase II) and hemoglobin (Hb). The interactions accorded with Langmuir isothermal adsorption; the saturation binding numbers for cyt c, DNase II and Hb were 42+/-5, 24+/-2 and 1.1+/-0.1 micromol/g nano-SiO(2) particle at pH 7.4, respectively, and the corresponding stability constants were 6.15 x 105, 1.79 x 106 and 2.6 x 107 M(-1). On the basis of the binding constants and of zeta-potential fluorescence and circular dichroism (CD) measurements and scanning electronic microscopy (SEM), it was found that the three functional proteins can bridge nano-SiO(2) particles via charge attraction and hydrogen bonding and aggregate them into coralloid forms. The interactions also changed the secondary structures of the proteins and inhibited their static and dynamic activities. It may reasonably be deduced that exposure to nano-size silicon dioxide particles e.g. as drug carriers may have an unfavorable effect on human health by inactivating functional proteins.
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PMID:Effects of nano-sized silicon dioxide on the structures and activities of three functional proteins. 2047 50

Interdigital tissue regression during embryonic development is one of the most representative model systems of morphogenetic cell death, but the degenerative cascade accounting for this process awaits clarification. Although the canonical apoptotic caspase pathway appears to be activated in the interdigital mesenchyme committed to die, neither genetic nor chemical blockage of caspases or their downstream effectors, is sufficient to prevent cell death. Hence, alternative and/or complementary dying pathways must also be responsible for this degenerative process. In this work we have chosen to study the endonucleases during the regression of the interdigital tissue of avian embryos to gain insights into the molecular mechanisms accounting for programmed cell death in this system. We show that caspase activated DNase, which is a neutral DNase associated with the caspase apoptotic pathway, appears to be the main endonuclease only at an initial phase of interdigit regression. However at peak stages of the degenerative process, the acidic DNases L-DNase II and lysosomal DNase IIB become predominant in the system and markers for cell autophagy become moderately up-regulated. Consistent with the activation of acidic endonucleases we observed that microenvironmental pH value in the interdigits decreased to levels only appropriate for acidic enzymes. Furthermore, we found that overexpression of lysosomal DNase IIB in embryonic limb mesoderm promoted cell death, which was also accompanied by up-regulation and activation of L-DNase II. Up-regulation of acidic DNases was maintained in interdigits explanted to culture dishes, where the participation of exogenous professional phagocytes of hematopoietic origin is avoided. Finally, and consistent with all our findings, up-regulation of acidic DNases was much reduced in the webbed interdigits of duck embryos, characterized by a rudimentary interdigital degenerative process. We conclude that the regression of the interdigital tissue involves a coordinated and sequential activation of the caspase and lysosomal degenerative molecular cascades.
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PMID:Coordinated and sequential activation of neutral and acidic DNases during interdigital cell death in the embryonic limb. 2061 51


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