Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.22.1 (DNase II)
 429 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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

Transition of bovine ribonuclease A from its monomeric to a dimeric form changes the pattern of enzymic activity response to ionic strength [Sorrentino, S., Carsana, A., Furia, A., Doskocil, J., and Libonati, M. (1980) Biochim. Biophys. Acta. 609, 40-52]. To see whether this phenomenon could be common to other enzyme-substrate systems, the action of various dimeric and monomeric enzymes (ox pancreas deoxyribonuclease, hog spleen acid deoxyribonuclease, bovine seminal ribonuclease, egg-white lysozyme, and papain) on polyelectrolytic substrates has been studied under different conditions of ionic strength. Dimerization of ox pancreas deoxyribonuclease, lysozyme and papain was obtained by cross-linkage with dimethyl suberimidate. The main results of the investigation, similar to those obtained with ribonuclease A, are the following. 1. Enzyme monomers and dimers show markedly different patterns of activity response to ionic strength at given pH values: the reactions catalyzed by monomeric enzymes are highly modulated by salt, whereas those catalyzed by dimeric enzymes are not. In particular, at the reaction optimum the monomeric form of an enzyme is significantly more active than the dimeric one. 2. The optimum of the reaction catalyzed by a dimeric enzyme is shifted to higher ionic strengths in comparison with that of the reaction catalyzed by a monomeric enzyme. A model is proposed that could explain these results on the basis of the influence of ionic strength on the intramolecular dynamics of the enzyme molecule and its non-specific interactions with polyelectrolytic substrates.
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PMID:Dimerization of deoxyribonuclease I, lysozyme and papain. Effects of ionic strength on enzymic activity. 628 87

We have used hydroxy-radical and deoxyribonuclease-I footprinting to probe the interaction of mithramycin with DNA fragments containing the sequences (AT)10X(AT)10 (X = CCCG, CCGC or CGGC) and A14GCCCT15. As expected the drug produces clear footprints located around the central four GC base pairs. The exact position of the footprint is different for the four sequences; the footprint with CCCG is displayed by two base pairs in the 5' direction relative to GCCC. These variations are explained by suggesting that mithramycin avoids the dinucleotide CG and binds better to GG/CC than GC. Although there is little change in deoxyribonuclease-I cleavage of the surrounding blocks of (AT)n, cleavage by deoxyribonuclease II is markedly enhanced and certain thymines on the 5' side of the ligand-binding site become hyperreactive to hydroxy-radical attack. Adjacent regions of An.Tn show enhanced rates of deoxyribonuclease-I cleavage in the presence of the antibiotic.
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PMID:DNA-sequence binding preference of the GC-selective ligand mithramycin. Deoxyribonuclease-I/deoxyribonuclease-II and hydroxy-radical footprinting at CCCG, CCGC, CGGC, GCCC and GGGG flanked by (AT)n and An.Tn. 839 9

We have cloned and sequenced novel cDNAs that encode human and murine DNase II, the acidic deoxyribonuclease. Sequence analysis predicts that huDNase II contains an N-terminal signal sequence and that mature DNase II has 344 residues with a calculated molecular mass of 38 032 Da. DNase II is a novel enzyme with no homologies to proteins of known function. Surprisingly, C. elegans appears to possess a family of DNase II homologs. Unlike DNase I-like enzymes that have tissue-specific expression patterns, huDNase II is ubiquituously expressed at low levels. When huDNase II is expressed in human 293 cells, we observe secretion of a novel 42-44 kDa glycoprotein; approximately 20-30% of recombinant human DNase II activity is secreted in this system. The secreted enzyme possesses DNA hydrolytic activity and shares biochemical properties with purified DNase II obtained from other species. We also show that the mechanism by which DNase II cuts DNA is similar to DNase I in that the enzyme produces nicks rather than double-strand cuts.
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PMID:Molecular cloning and characterization of human and murine DNase II. 971 27

A deoxyribonuclease (DNase) which is active at acid pH in the absence of bivalent cations was found in loach spermatozoa. The enzyme was purified by ion-exchange chromatography and partially characterized. The DNase has optimal activity at pH 5.5 and its molecular weight is about 30 kD; its substrate is covalently closed circular duplex DNA, and its product is the corresponding unit-length linear DNA. The DNase is inhibited by MgCl2 and activated by EDTA. Thus, this endoDNase found in loach spermatozoa can be classified as a DNase II. The biological role of this DNase II is discussed.
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PMID:DNase II in spermatozoa of the loach misgurnus fossilis L 1038 8

DNase II is a well-known deoxyribonuclease (DNase) that catalyzes the hydrolysis of DNA into oligonucleotides under acidic conditions. We have identified a novel DNase that shows homology to DNase II, named DLAD, from a search of an expressed sequence tag data base. The full-length cDNA for rat DLAD cloned by polymerase chain reaction encodes a 356-amino acid polypeptide containing a putative N-terminal signal peptide and 5 potential N-glycosylation sites; there is a predicted catalytic domain resemblance to rat DNase II. The predicted DLAD translation product shares 32.9% identity with DNase II. Interestingly, expression of the DRAD mRNA is highly restricted to the liver. A Myc-His tagged recombinant DLAD recovered mainly from the cytoplasm of transfected HeLa S3 cells has a divalent cation-independent DNase activity. The DLAD activity prefers acidic conditions to neutral. The recombinant protein expressed in HeLa S3 cells inhibits the expression of GFP- and lac Z-expression vectors, suggesting that DLAD may play a role in elimination of exogenous DNA. Identification of the full-length cDNA for DLAD would lead to an understanding of the physiology of this DNase II-like molecule.
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PMID:Cloning of a cDNA encoding a rat DNase II-like acid DNase. 1055 78

Acidic endonuclease activity is present in all cells in the body and much of this can be attributed to the previously cloned and ubiquitously expressed deoxyribonuclease II (DNase II). Database analysis revealed the existence of expressed sequence tags and genomic segments coding for a protein with considerable homology to DNase II. This report describes the cloning of this cDNA, which we term deoxyribonuclease IIbeta (DNase IIbeta) and comparison of its expression to that of the originally cloned DNase II (now termed DNase IIalpha). The cDNA encodes a 357 amino acid protein. This protein exhibits extensive homology to DNase IIalpha including an amino-terminal signal peptide and a conserved active site, and has many of the regions of identity that are conserved in homologs in other mammals as well as C. elegans and Drosophila. The gene encoding DNase IIbeta has identical splice sites to DNase IIalpha. Human DNase IIbeta is highly expressed in the salivary gland, and at low levels in trachea, lung, prostate, lymph node, and testis, whereas DNase IIalpha is ubiquitously expressed in all tissues. The expression pattern of human DNase IIbeta suggests that it may function primarily as a secreted enzyme. Human saliva was found to contain DNase IIalpha, but after immunodepletion, considerable acid-active endonuclease remained which we presume is DNase IIbeta. We have localized the gene for human DNase IIbeta to chromosome 1p22.3 adjacent (and in opposing orientation) to the human uricase pseudogene. Interestingly, murine DNase IIbeta is highly expressed in the liver. Uricase is also highly expressed in mouse but not human liver and this may explain the difference in expression patterns between human and mouse DNase IIbeta.
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PMID:The cloning, genomic structure, localization, and expression of human deoxyribonuclease IIbeta. 1137 52

Nuclease footprinting techniques were initially developed to investigate protein-deoxyribonucleic acid (DNA) interactions but these tools of molecular biology have also become instrumental for probing sequence-selective binding of small molecules to DNA. Here, the method is described and technical details are given for performing deoxyribonuclease (DNase) I footprinting with DNA-binding drugs. An example is presented where DNase I is used (as well as DNase II and micrococcal nuclease) to probe the patterns of sequence-selective recognition of DNA by the anticancer antibiotic actinomycin D. DNase I is a convenient endonuclease for detecting and locating the position of actinomycin-binding sites within GC-rich sequences.
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PMID:DNase I footprinting of small molecule binding sites on DNA. 1533 13

A new acid deoxyribonuclease (DNase) was purified from the cultured mycelia of Cordyceps sinensis, and designated CSDNase. CSDNase was purified by (NH(4))(2)SO(4) precipitation, Sephacryl S-100 HR gel filtration, weak anion-exchange HPLC, and gel filtration HPLC. The protein was single-chained, with an apparent molecular mass of ca. 34 kDa, as revealed by SDS-PAGE, and an isoelectric point of 7.05, as estimated by isoelectric focusing. CSDNase acted on both double-stranded (ds) and single- stranded (ss) DNA, but preferentially on dsDNA. The optimum pH of CSDNase was pH 5.5 and its optimum temperature 55. The activity of CSDNase was not dependent on divalent cations, but its enzymic activity was inhibited by high concentration of the cation: MgCl(2) above 150 mM, MnCl(2) above 200 mM, ZnCl(2) above 150 mM, CaCl(2) above 200 mM, NaCl above 300 mM, and KCl above 300 mM. CSDNase was found to hydrolyze DNA, and to generate 3-phosphate and 5-OH termini. These results indicate that the nucleolytic properties of CSDNase are essentially the same as those of other well-characterized acid DNases, and that CSDNase is a member of the acid DNase family. To our knowledge, this is the first report of an acid DNase in a fungus.
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PMID:Purification and characterization of an acid deoxyribonuclease from the cultured mycelia of Cordyceps sinensis. 1546 35

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


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