Triosephosphate isomerase tyrosine nitration induced by heme–NaNO 2 –H 2 O 2 or peroxynitrite: Effects of different natural phenolic compounds

Peroxynitrite and heme peroxidases (or heme)–H 2 O 2 –NaNO 2 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 2 O 2 –NaNO 2 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 2 O 2 –NaNO 2 and SIN‐1 and protein oxidation induced by SIN‐1, but promoted heme–H 2 O 2 –NaNO 2 ‐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 2 O 2 –NaNO 2 ‐induced nitration. Our results indicated that peroxynitrite and heme–H 2 O 2 –NaNO 2 ‐induced protein nitration was different, and the later one could be a better model for anti‐nitration compounds screening.