Kinetic and spectroscopic characterization of an intermediate peroxynitrite complex in the nitrogen monoxide induced oxidation of oxyhemoglobin (vol 439, pg 85, 1998)

Stopped-flow spectroscopy studies of the nitrogen monoxide mediated oxidati on of oxyhemoglobin in the pH range 5-10.5 show that an intermediate can be characterized at alkaline pH. The rate of decay of this species to methemo globin increases significantly with decreasing pH such that it does not acc umulate in quantities large enough to be observed under neutral or acidic c onditions. Kinetic and spectroscopic properties of this intermediate suppor t its assignment as a methemoglobin peroxynitrite complex. (C) 1999 Federat ion of European Biochemical Societies.