Effect of superoxide dismutase mimics on radical adduct formation during the reaction between peroxynitrite and thiols--an ESR-spin trapping study. Arch Biochem Biophys 1996 Jun 01;330(1):115-24
Date
06/01/1996Pubmed ID
8651684DOI
10.1006/abbi.1996.0232Scopus ID
2-s2.0-0029947061 (requires institutional sign-in at Scopus site) 16 CitationsAbstract
We have reexamined the formation and reactions of radicals formed from peroxynitrite (ONOO-)-mediated oxidation of glutathione (GSH), L-cysteine (Cys), N-acetyl-D,L-penicillamine (NAP), and sodium bisulfite (NaHSO3). Sulfur-centered and superoxide union radicals were trapped using 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) and the radical adducts were analyzed by electron spin resonance (ESR) spectroscopy. The following sulfur-centered radicals were detected: glutathionyl radical (GS') from GSH, L-cysteinyl radical ('Scys) from L-cysteine, N-acetyl-D,L-penicillamine thiyl radical ('SNAP) from NAP, and sulfite anion radical (SO3-.) from NaHSO3. Additionally the formation of the hydroxyl radical adduct of DMPO (DMPO/'OH) was observed. DMPO/'OH formation was totally inhibited by low-molecular-weight superoxide dismutase (SOD) mimics. This suggests that DMPO/'OH was formed from the decay of the superoxide radical adduct of DMPO. In the presence of SOD mimics, the DMPO-sulfur-centered adducts were more persistent, suggesting that O2-. is partially responsible for the instability of DMPO-thiyl adducts. Sulfur-centered radicals formed during oxidation of thiols and sulfite by peroxynitrite react with ammonium formate to form the carbon dioxide anion radical (CO2-.). We conclude that sulfur-centered radicals produced from the oxidation of thiols and sulfite by peroxynitrite arise from a hydroxyl-radical-independent mechanism. Biological implications of peroxynitrite-mediated oxidation of thiols as well as the use of SOD mimics in biological spin-trapping are discussed.
Author List
Karoui H, Hogg N, Joseph J, Kalyanaraman BAuthors
Neil Hogg PhD Associate Dean, Professor in the Biophysics department at Medical College of WisconsinBalaraman Kalyanaraman PhD Professor in the Biophysics department at Medical College of Wisconsin
MESH terms used to index this publication - Major topics in bold
Cyclic N-OxidesCysteine
Electron Spin Resonance Spectroscopy
Free Radical Scavengers
Free Radicals
Glutathione
Glutathione Disulfide
Kinetics
Nitrates
Organometallic Compounds
Oxygen
Penicillamine
Spin Labels
Sulfhydryl Compounds
Sulfites
Superoxide Dismutase
Superoxides