Fig. 1
Determination of kcat of FP15 toward peroxynitrite decomposition. Reaction was carried out in PBS pH 7.4 in the absence (closed square) or presence (closed diamond) of 10 mM of bicarbonate. Concentration of FP15 was varied 0–8 µM, peroxynitrite was maintained at ~100 µM. FP15 concentration was plotted against the observed rate constant of peroxynitrite decay. Kobs is obtained from first-order fit of absorbance decay at 302 nm. The plot shows a nonlinear dependence that suggests involvement of two distinct reaction pathways, as proposed elsewhere (19).