Mechanistic studies of DNA and RNA oxidation by macrocyclic nickel complexes.

(1) Background: The products of guanine oxidation in DNA and RNA excreted in urine are 8-oxo-7,8-dihydroguanine (8-oxoGua), 8-oxo-7,8-dihydroguanosine (8-oxoGuo), and 8-oxo-7,8-dihydro-2’-deoxyguanosine (8-oxodGuo). Despite intra and inter-individual variability, it is possible to identify situations that significantly increase the levels of these compounds when comparing urinary concentrations of some workers to those of the general population. (2) Methods: urines from gasoline pump attendants (58 from Saudi Arabia and 102 from Italy), 24 workers of a fiberglass reinforced plastics plant, 17 painters and 6 divers were analyzed by HPLC/MS-MS. To test the individual variability, two subjects provided daily samples for one month, and 132 urine samples from the general population were analyzed. (3) Results: We summarized the results for each biomarker, and found the following were statistically higher than in the general population: 8-oxoGua in fiberglass and Italian gasoline workers; 8-oxodGuo in fiberglass and both Saudi Arabian and Italian gasoline workers; 8-oxoGuo in fiberglass workers, both Saudi Arabian and Italian gasoline workers, and painters after the working shift. (4) Conclusions: these results confirm that both 8-oxodGuo and 8-oxoGuo are valuable biomarkers for occupational exposures to dangerous chemicals and seem to suggest that 8-oxoGuo, related to RNA oxidation, is a suitable biomarker to evaluate short term, reversible effects of occupational exposures even within the health-based limit values.

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Proteasome inhibition increases DNA and RNA oxidation in astrocyte and neuron cultures

Journal of Neurochemistry ◽

10.1111/j.1471-4159.2004.02802.x ◽

2004 ◽

Vol 91 (5) ◽

pp. 1211-1218 ◽

Cited By ~ 35

Author(s):

Qunxing Ding ◽

Edgardo Dimayuga ◽

William R. Markesbery ◽

Jeffrey N. Keller

Keyword(s):

Proteasome Inhibition ◽

Dna And Rna ◽

Rna Oxidation

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Protonation mechanisms of Nickel Complexes Relevant to Industrial and Biological Catalysis

Journal of Chemical Research ◽

10.3184/030823402103172554 ◽

2002 ◽

Vol 2002 (9) ◽

pp. 407-411 ◽

Cited By ~ 6

Author(s):

Richard A. Henderson

Keyword(s):

Metal Complexes ◽

Binding Site ◽

Molecular Level ◽

Nickel Complexes ◽

Mechanistic Studies ◽

Thermodynamic Control ◽

Biological Catalysis ◽

Rearrangement Reactions ◽

Initial Binding

The sites of protonation and the subsequent rearrangement reactions of simple nickel complexes containing hydride, thiolate and alkyl ligands are reviewed, and the relevance of these reactions to the action of certain nickelbased catalysts are discussed. Summary Protonation at the metal and ligand is central to the understanding of how both enzymes and industrial catalysts operate at the molecular level. The recurring theme in studies on the protonation of all metal complexes is that the ultimate residence of the proton is not necessarily the initial binding site, and the movement of proton between sites can occur by a variety of mechanisms. These features are also evident in the reactions of simple nickel complexes and mechanistic studies are revealing the subtle interplay between ligand and metal which are the basis of the kinetic and thermodynamic control of protonation reactions at these sites.

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