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

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.
 ...
PMID:Preparation and enzymatic hydrolysis of dinucleoside monophosphates and DNA modified with aromatic residues. 55 43

Liver nuclei were prepared through the first cell cycle in partially hepatectomized young rats showing 30% parenchymal cell synchrony. To determine if nucleosome structure altered during this period, liver nuclei from sham-operated rats were compared with nuclei isolated at various times after partial hepatectomy. These nuclei were exposed to deoxyribonuclease I (EC 3.1.4.5), deoxyribonuclease II (EC 3.1.4.6) or micrococcal nuclease (EC 3.1.4.7) and the nucleosome-associated DNA length was ascertained. In no case was a difference in the DNA lengths associated with nucleosome structure observed. Differences were observed with regard to the histones and their relative association with nuclear material. When nuclei from normal rat livers were incubated in hypo-osmolar medium 9% of histone 1 and 4% of the other histones were released. These released histones, unlike those remaining bound to the nuclei, showed high [3H]adenosine and [3H]acetate uptakes in vivo. [32P]P1 uptake was also much greater into released than bound histones 1 and 3, but was not different for histone2A. At 3.5-4.5 h after partial hepatectomy, the release of histone 1 was trebled and that of histone 4 doubled. By 13.5 h, when phosphorylation of the bound forms of histones 2A and especially 1 was increased, no further changes in histone release in hypo-osmolar medium were found. The released histones from partially hepatectomized livers had indistinguishable [3H]adenosine uptakes from controls. The roles are discussed of phosphorylation and ADP-ribosylation in labilizing histone binding.
 ...
PMID:Chromatin structure through the cell cycle. Studies with regeneration rat liver. 70