Peroxynitrite-mediated oxidation of albumin to the protein-thiyl free radical.
Nitric oxide reacts with superoxide to produce peroxynitrite, which may be an important mediator of oxidant-induced cellular injury. Here we report that peroxynitrite is able to oxidize a protein, bovine serum albumin (BSA), to the corresponding protein-thiyl free radical as demonstrated by electron paramagnetic resonance (EPR)-spin-trapping experiments with both alpha-phenyl-N-tert-butyl nitrone (PBN) and 5,5-dimethyl-1-pyrroline-N-oxide (DMPO). BSA radical adduct yields increased with pH indicating peroxynitrite anion as its main forming agent. Reaction with peroxynitrite may be another aspect of the antioxidant action of albumin in extracellular fluids.
Department of Biochemistry, Universidade de São Paulo, Brazil.
R M
RM
Gatti
R
R
Radi
O
O
Augusto
D003497:Cyclic N-Oxides; D004578:Electron Spin Resonance Spectroscopy; D005609:Free Radicals; D006863:Hydrogen-Ion Concentration; D009566:Nitrates / Q000378:metabolism*; D009589:Nitrogen Oxides; D010084:Oxidation-Reduction; D012710:Serum Albumin, Bovine / Q000737:chemistry / Q000378:metabolism*; D013113:Spin Labels
D003497:Cyclic N-Oxides; D005609:Free Radicals; D009566:Nitrates; D009589:Nitrogen Oxides; D013113:Spin Labels; C039642:peroxynitric acid; D012710:Serum Albumin, Bovine; C029217:phenyl-N-tert-butylnitrone; C017245:5,5-dimethyl-1-pyrroline-1-oxide