Evidence for peroxynitrite formation during S-nitrosoglutathione photolysis in air saturated solutions

Flash photolysis of S-nitrosoglutathione (GSNO) in aerated solutions at pH 10 gave rise to an absorption with a maximum around 310-320 nm, This peal i s spectrally similar to that display ed by ONOO-. The decay kinetics of thi s absorption mas compared to that of authentic ONOO-, generated independent ly. An excellent correlation was obtained. Further proof of ONOO- generatio n aas provided by HPLC studies showing the production of 3-nitrotyrosine on irradiation of GSNO in the presence of tyrosine at pH 7.4, In addition, th e nitration yield nas increased similar to 5-fold in the presence of bicarb onate and totally eliminated,vith DMPO, indicating the requirement of a rad ical intermediate for peroxynitrite production during S-nitrosothiol photol ysis. (C) 1999 Federation of European Biochemical Societies.