Cellular Concentrations of Nucleotide Diphosphate-Chelated Magnesium Ions Accelerate Catalysis by RNA and DNA Enzymes

Avian bone marrow has been found to contain a phosphodiesterase as well as an acid phosphatase. Some properties of these enzymes have been described. Because the phosphodiesterase of this tissue has an alkaline pH optimum, is activated by magnesium ions, and acts on the specific substrate p-nitrophenyl thymidine 5′-phosphate, it is probably a phosphodiesterase I such as is present in snake venom and other tissues.The intracellular distribution of these two enzymes in normal and regenerating bone marrow was studied. Subcellular fractions were prepared by differential centrifugation or by centrifugation through sucrose density gradients. The RNA and DNA content of each fraction was determined. By the methods used no differences in the properties or intracellular distribution of the two enzymes in normal and regenerating bone marrow were found.

Download Full-text

Chemical Reactions with RNA and DNA Enzymes

Molecular Encapsulation ◽

10.1002/9780470664872.ch14 ◽

2010 ◽

pp. 377-396 ◽

Cited By ~ 2

Author(s):

Andres Jäschke

Keyword(s):

Chemical Reactions ◽

Dna Enzymes ◽

Rna And Dna

Download Full-text

Therapeutic RNA and DNA enzymes

Biochemical Pharmacology ◽

10.1016/s0006-2952(00)00395-6 ◽

2000 ◽

Vol 60 (8) ◽

pp. 1023-1026 ◽

Cited By ~ 7

Author(s):

Mouldy Sioud ◽

Marianne Leirdal

Keyword(s):

Dna Enzymes ◽

Rna And Dna

Download Full-text

Observations of the Thermal Decomposition of Brucite

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100101980 ◽

1968 ◽

Vol 26 ◽

pp. 446-447

Author(s):

P. L. Burnett ◽

W. R. Mitchell ◽

C. L. Houck

Keyword(s):

Thermal Decomposition ◽

Magnesium Oxide ◽

Basal Plane ◽

Magnesium Ions ◽

A Value ◽

Reaction Proceeds

Natural Brucite (Mg(OH)2) decomposes on heating to form magnesium oxide (MgO) having its cubic ﹛110﹜ and ﹛111﹜ planes respectively parallel to the prism and basal planes of the hexagonal brucite lattice. Although the crystal-lographic relation between the parent brucite crystal and the resulting mag-nesium oxide crystallites is well known, the exact mechanism by which the reaction proceeds is still a matter of controversy. Goodman described the decomposition as an initial shrinkage in the brucite basal plane allowing magnesium ions to shift their original sites to the required magnesium oxide positions followed by a collapse of the planes along the original <0001> direction of the brucite crystal. He noted that the (110) diffraction spots of brucite immediately shifted to the positions required for the (220) reflections of magnesium oxide. Gordon observed separate diffraction spots for the (110) brucite and (220) magnesium oxide planes. The positions of the (110) and (100) brucite never changed but only diminished in intensity while the (220) planes of magnesium shifted from a value larger than the listed ASTM d spacing to the predicted value as the decomposition progressed.

Download Full-text

The Effect of Agents which Modify Platelet Behaviour and of Magnesium Ions on Thrombus Formation In Vivo

Thrombosis and Haemostasis ◽

10.1055/s-0038-1666898 ◽

1979 ◽

Vol 42 (02) ◽

pp. 603-610 ◽

Cited By ~ 59

Author(s):

J H Adams ◽

J R A Mitchell

Keyword(s):

Thrombus Formation ◽

Cerebral Arteries ◽

Magnesium Ions ◽

Body Formation ◽

Inflammatory Agent ◽

Platelet Thrombus ◽

Magnesium Salts ◽

Higher Doses ◽

Do So

SummaryThe ability of potential anti-thrombotic agents to modify platelet-thrombus formation in injured cerebral arteries in the rabbit was tested. Low doses of heparin were without effect, while higher doses produced variable suppression of white body formation but at the expense of bleeding. Aspirin did not inhibit white body formation but another non-steroid anti-inflammatory agent, flurbiprofen was able to do so, as was the anti-gout agent, sulphinpyrazone. Magnesium salts both topically and parenterally, suppressed thrombus formation and increased the concentration of ADP which was required to initiate thrombus production at minor injury sites.

Download Full-text