Triosephosphate isomerase tyrosine nitration induced by heme-NaNO -H O or peroxynitrite: Effects of different natural phenolic compounds.

Peroxynitrite and heme peroxidases (or heme)-H O -NaNO system are the two common ways to cause protein tyrosine nitration in vitro, but the effects of antioxidants on reducing these two pathways-induced protein nitration and oxidation are controversial. Both nitrating systems can dose-dependently induce triosephosphate isomerase (TIM) nitration, however, heme-H O -NaNO was less destructive to protein secondary structures and led to more nitrated tyrosine residue than 3-morpholinosydnonimine hydrochloride (SIN-1, a peroxynitrite donor). Both of desferrioxamine and catechin could inhibit TIM nitration induced by heme-H O -NaNO and SIN-1 and protein oxidation induced by SIN-1, but promoted heme-H O -NaNO -induced protein oxidation. Moreover, the antagonism of natural phenolic compounds on SIN-1-induced tyrosine nitration was consistent with their radical scavenging ability, but no similar consensus was found in heme-H O -NaNO -induced nitration. Our results indicated that peroxynitrite and heme-H O -NaNO -induced protein nitration was different, and the later one could be a better model for anti-nitration compounds screening.