Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.31.1 (micrococcal nuclease)
 2,818 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Small oligonucleotides from DNA and RNA have been separated according to their base composition by high-performance anion-exchange liquid chromatography on Partisil-10 SAX using triethylammonium acetate buffer as the eluent. Fifteen of the 16 possible deoxydinucleoside monophosphates and all 16 dinucleoside monophosphates have been separated. All pairs of sequence isomers were all resolved. The 15 commercially available deoxydinucleotides were resolved into 13 fractions. A good resolution of deoxytrinucleoside diphosphates isolated from an alkaline phosphatase-Mg2+-activated DNase I digest of calf thymus DNA was achieved by this technique. A large number of sequence isomers could be fully separated. The base sequence of the eluted individual constituents has been determined by their hydrolysis with snake venom and spleen phosphodiesterase followed by high-performance liquid chromatographic analysis of the nucleotides released. The eight trinucleoside diphosphates isolated from an alkaline phosphatase-pancreatic RNase digest of yeast RNA have also been separated according to base composition. Their sequence was determined as above. The described technique is fast and gave very good separation. Most of the sequence isomers could be separated. Moreover, the eluent triethylammonium acetate can easily be removed from column effluents by freeze-drying in order to facilitate subsequent sequence analysis of the eluted compounds. The observed elution orders of the sequence isomers obey certain rules which are discussed in detail.
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PMID:Separation of small DNA and RNA oligonucleotides by high-performance anion-exchange liquid chromatography. 9 13

Free ribosomes extracted from hamster cells and 28S RNA purified from these ribosomes are known to form dimers. We find that spleen phosphodiesterase inhibits ribosomal dimer formation, but only when a free 5'-hydroxyl end group, produced by the action of alkaline phosphatase, is present. Hence, formation of dimer ribosomes probably involves interaction at or near the phosphorylated 5'-ends of 28S RNA. Dimer RNA molecules show a modal length, when measured on electrom micrographs, of 2.1 mum, which is about double the length of 28S RNA. Electron micrographs of 115S dimer ribosomes often show profiles consistent with our interpretation that in dimers the 28S RNA chains are loosely linked by their 5'-ends.
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PMID:Interaction of the 5'-ends of 28S RNA in dimerization of hamster ribosomes. 16 35

T4 endonuclease V, which is involved in repair of ultraviolet-damaged DNA, has been purified 3600 fold from T4D-infected Escherichia coli. The enzyme shows optimal activity at pH 7.2 and does not require added divalent ions. Endonuclease V attacks both native and heat-denatured DNA provided that the DNA has been irradiated, and the enzyme activity is dependent on the dose of ultraviolet irradiation. The rate and the extent of the reaction are greater with irradiated native DNA although the Km values for the two types of DNA are the same (2.25 - 10(-5) M). The enzyme is readily inactivated by heat and is sensitive to p-chloromercuribenzoate. Endonuclease V-treated irradiated DNA is degraded by spleen phosphodiesterase only when the DNA has been treated with alkaline phosphatase, suggesting that the enzyme produces 5'-phosphoryl termini.
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PMID:Further purification and characterization of T4 endonuclease V. 18 58

Because of their association with protein short nascent DNA chains in Escherichia coli can be separated from other cellular DNA by chromatography on hydroxylapatite. Protein-free DNA chains of less than 500 nucleotides in length are resistant to degradation from the 5'-end by alkaline phosphatase [orthophosphoric-monoester phosphohydrolase (alkaline optimum); EC 3.1.3.1] and spleen phosphodiesterase (oligonucleate 3'-nucleotidohydrolase; EC 3.1.4.18). In contrast, DNA chains containing more than 500 nucleotides are degradable. From these results we conclude that short nascent DNA chains are structurally modified at their 5'-ends. The nature of this structure and its possible functions are discussed.
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PMID:Novel structure at 5'-ends of nascent DNA chains. 18 11

A procedure is reported for the isolation of cross-linked nucleosides from nitrous acid-treated calf thymus DNA. Cross-linked DNA was hydrolyzed enzymatically with deoxyribonuclease I and snake venom phosphodiesterase and fractionated on a DEAE-Sephadex column. After desalting, the fractions were characterized by ultraviolet spectroscopy, anion exchange high pressure liquid chromatography, gel filtration, and two dimensional thin layer chromatography. A cross-linked dinucleotide, and a series of oligonucleotides were isolated. The oligomers, which had resisted digestion by the above enzyme system, were digested to the nucleoside level by a spleen phosphodiesterase-alkaline phosphatase combination. A second cross-linked product was isolated from this mixture. The cross-linked nucleosides were less than 0.17% of the total nucleotides of the DNA. The methods developed here are recommended for the isolation of products from DNA treated with other cross-linking agents.
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PMID:A method for the isolation of cross-linked nucleosides from DNA: application to cross-links induced by nitrous acid. 19 94

Aqueous solutions of DNA were gamma-irradiated in the presence and absence of oxygen and enzymatically hydrolysed by the combined action of pancreatic deoxyribonuclease (DNase I), snake-venom phosphodiesterase (PDE I), spleen phosphodiesterase (PDE II) and alkaline phosphatase. In contrast to unirradiated DNA, which is fully hydrolysed to nucleosides by these enzymes, gamma-irradiated DNA yields a series of oligonucleotides. Their isolation might enalbe the future identification of the chemical nature of DNA lesions.
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PMID:Enzymatic digestion of DNA gamma-irradiated in aqueous solution separation of the digests by ion-exchange chromatography. 21 Jan 33

A dialysable low-molecular-weight factor capable of affecting in vitro properties of macrophages was extracted from four different mouse tumors. This factor not only modulates closely related properties of peritoneal macrophages such as spreading and migration but also inhibits lipopolysaccharde-induced tumoricidal activity of these cells. It can be extracted not only from tumor tissues but also from tumor cells grown in vitro. The appearance of this factor is unique to tumors and it is not present in detectable quantities in normal tissues. The factor from one of the tumors, Lewis lung carcinoma, was purified extensively and the partially purified factor retains all the above effects on macrophages. It is not sensitive to pronase or a mixture of bovine spleen phosphodiesterase II, E. coli alkaline phosphatase and pancreatic ribonuclease. The factor is lipid-like in character and it is soluble in both organic solvents and aqueous media. It has ionizable group(s) and is anionic at neutral pH but non-ionic under acidic conditions.
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PMID:Characteristics of a low-molecular-weight factor extracted from mouse tumors that affects in vitro properties of macrophages. 22 Jan 97

The following procedures have been used to prepare fifteen modified dinucleoside monophosphates: (a) bisulfite-catalyzed transamination with aniline to give an N4-phenylcytidine (CPh), (b) bisulfite-catalyzed transamination with beta-naphthylamine to give an N4-beta-naphthylcytidine (CbetaN), (c) alkylation with 7-bromomethylbenz[a] anthracene to afford a 7(benz[a]anthryl-7-methyl)guanosine (GMBA), and (d) reaction with N-acetoxy-2-acetylaminofluorene to give an 8-(N-2-fluorenylacetamido)guanosine (GAAF). The compounds prepared were A-CPh, CPh-A, CPh-G, U-CPh, CPh-U, A-CbetaN, CbetaN-A, G-CbetaN, CbetaN-G, U-CbetaN, CbetaN-U, GMBA-U, U-GMBA, GAAF-U, and U-GAAF. All of the modified compounds were hydrolyzed to the expected monomers with venom and spleen exonucleases. Hydrolysis by micrococcal nuclease was inhibited in the following cases: A-CPh, A-CbetaN, U-GMBA, and U-GAAF. The first three reactions above were applied to denatured calf thymus DNA to prepare modified DNA samples containing from 0.3 to 2.0% bound aromatic residues. The modified nucleic acids were completely hydrolyzed to nucleosides by the combination of venom exonuclease, deoxyribonuclease I and alkaline phosphatase. The same results were obtained with a combination of spleen exonuclease, deoxyribonuclease II, and alkaline phosphatase. Hydrolysis of the modified nucleic acids by micrococcal nuclease and alkaline phosphatase afforded primarily nucleosides, with some dinucleoside monophosphates. The amount of the latter did not exceed that found in the hydrolysis of control DNA, however. Other workers have observed inhibition of enzymatic hydrolysis of nucleic acids modified by aromatic carcinogens. We postulated that their results may have been caused by cross-links, which were avoided in our studies.
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PMID:Preparation and enzymatic hydrolysis of dinucleoside monophosphates and DNA modified with aromatic residues. 55 43

L cell DNA ligase catalyzes a covalent linkage between 5'-hosphoryl oligodeoxyribonucleotides and 3'-hydroxyl oligoribonucleotides on a complementary polydeoxyribonucleotide template. This reaction occurs to a substantially lesser extent than does the sealing of DNA to DNA. The joining of [5'32P]d(pA)12-18 to (Ap)11A on poly[d(T)] or of [5'-32P]d(pG)12-18 to 5'-hydroxyl, 3'-hydroxyl oligo(I) ON POLY[D(C)] was demonstrated by the formation of alkaline phosphatase resistant radioactivity. The 32P of the hybrid reaction products became sensitive to the action of alkaline phosphatase after treatment with alkali. Furthermore, hydrolysis of the products of the linkage of [5'-32P]d(pG)12-18 to 5'-hydroxyl, 3'-hydroxyl oligo(I) on poly[d(C)] with micrococcal nuclease and spleen phosphodiesterase resulted in the formation of [3'-32P]IMP. Attempts to seal [5'-32p[-(pA)12 to d(Ap)11-17A on poly[d(T) or [5'-32P]oligo(pI) to d(Gp)11-17G on poly[d(C)] were unsuccessful.
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PMID:L cell DNA ligase joins RNA to DNA on a DNA template. 87 16

RNA ligase isolated from Escherichia coli infected with bacteriophage T4 will catalyze the formation of an intermolecular 3' leads to 5' phosphodiester linkage between an oligoribonucleotide with a free 3'-hydroxyl and another oligoribonucleotide with a 5'-phosphate. Upon reaction with (Ap)5C, nearly quantitative conversion of the hexamer [5'-32P]p(Up)5U to the dodecamer (Ap)5C[3' leads to 5'-32P]p(Up)5U was observed. The product was identified by its mobility on RPC-5 column chromatography, its resistance to alkaline phosphatase, and the appearance of the expected radiolabeled products on hydrolysis with alkali, ribonuclease A, snake venom phosphodiesterase, and spleen phosphodiesterase. The coupling of other pairs of single-stranded oligoribonucleotides has also been demonstrated. The intermolecular joining reaction is probably mechanistically similar to the intramolecular cyclization activity previously reported for Tr RNA ligase. It is expected that this enzyme will be useful for the synthesis of RNA fragments of defined sequence.
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PMID:T4-induced RNA ligase joins single-stranded oligoribonucleotides. 109 Sep 29


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