These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Detection and characterization of the electron paramagnetic resonance-silent glutathionyl-5,5-dimethyl-1-pyrroline N-oxide adduct derived from redox cycling of phenoxyl radicals in model systems and HL-60 cells.
    Author: Stoyanovosky DA, Goldman R, Jonnalagadda SS, Day BW, Claycamp HG, Kagan VE.
    Journal: Arch Biochem Biophys; 1996 Jun 01; 330(1):3-11. PubMed ID: 8651701.
    Abstract:
    The antioxidant function of glutathione includes enzymatic reduction of hydrogen peroxide by glutathione peroxidase and nonenzymatic reduction of organic radicals and reactive oxygen species. The glutathionyl S-centered radical, formed by the nonenzymatic reduction process, is a marker of oxidative reactions proceeding by radical mechanisms. Spin-adducts of glutathionyl radicals with the spin trap DMPO, 5,5-dimethyl-1-pyrroline N-oxide, are not sufficiently stable and can be detected only under steady-state conditions. We developed a novel HPLC method for the detection of an EPR-silent DMPO adduct of glutathionyl radicals in model systems and in cells. We synthesized a sufficient quantity of the adduct for characterization by UV spectrophotometry, ionspray mass spectrometry, and 1H NMR spectroscopy. The UV absorption lambda max of the adduct, 258 nm, was indicative of a 2-(S-alkylthiyl)pyrroline N-oxide chromophore. The molecular mass of the adduct was 418 amu. No signal for the C2 proton of the DMPO-derived portion of the adduct was evident in its 1H NMR spectrum. The results were consistent with the structure 2-(S-glutathionyl)-5,5-dimethyl-1-pyrroline N-oxide (GS-DMPO nitrone). We showed that this adduct accumulated in the course of peroxidase-dependent redox cycling of phenol in the presence of glutathione and DMPO as well as in HL-60 cells exposed to a phenol/H2O2/DMPO reaction mixture. The EPR-silent GS-DMPO nitrone was readily assayed by HPLC under conditions incompatible with the detection of the GS-DMPO nitroxide by EPR. This is to our knowledge the first direct experimental evidence for the redox cycling of phenol in this bone marrow-derived cell line. The method may prove useful in the study of radical-driven oxidations of glutathione in various pathophysiological processes associated with radical mechanisms.
    [Abstract] [Full Text] [Related] [New Search]