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Palladium or platinum exacerbates hydroxyl radical mediated DNA damage
1School of Medical Technology, Chang Gung College of Medicine and Technology, Taoyuan Taiwan.
Free Radical Biology & Medicine
|January 1, 1997
Summary
Palladium (Pd) and platinum (Pt) ions enhance DNA strand breakage by Fenton systems by increasing hydroxyl radical (OH.) production. These metal ions promote OH. generation, leading to greater DNA damage.
Area of Science:
- Biochemistry
- Molecular Biology
- Environmental Chemistry
Background:
- The Fenton reaction is a chemical process involving iron and hydrogen peroxide that generates highly reactive hydroxyl radicals (OH.).
- Hydroxyl radicals are known to cause damage to biological molecules, including DNA.
- The role of other transition metal ions in modulating Fenton chemistry and subsequent DNA damage is an area of ongoing research.
Purpose of the Study:
- To investigate the effect of palladium (Pd) and platinum (Pt) ions on DNA strand breakage induced by a Fenton system.
- To determine if Pd and Pt ions influence the production of hydroxyl radicals (OH.) in the Fenton reaction.
- To elucidate the mechanism by which Pd and Pt ions might exacerbate DNA damage.
Main Methods:
- Supercoiled pBR322 DNA strand breakage assays.
- Spectrophotometric quantification of hydroxylated salicylate.
- Fluorometric quantification of catechol production.
- High-performance liquid chromatography (HPLC) for product identification.
- Electron spin resonance (ESR) spectroscopy to detect hydroxyl radical adducts.
Main Results:
- Pd and Pt ions significantly increased DNA strand breakage in the presence of a Fenton system.
- Both Pd and Pt ions augmented hydroxyl radical (OH.) production, as evidenced by increased hydroxylated salicylate and catechol levels.
- HPLC analysis confirmed the elevated production of specific hydroxylated salicylate products (2,3-dihydroxybenzoate, 2,5-dihydroxybenzoate, and catechol) with Pd addition.
- ESR spectroscopy detected HO-DMPO spin adducts, further supporting enhanced OH. generation.
Conclusions:
- Pd and Pt ions do not substitute for iron in the Fenton system but act as promoters.
- The exacerbation of DNA damage by Pd or Pt ions is mediated by their ability to promote hydroxyl radical (OH.) production.
- These findings highlight the potential for certain metal ions to amplify oxidative stress and DNA damage through Fenton-like reactions.