Figure 8

Quantification and distribution of the oxidized products generated after oxidation of Trp, Met and Tyr residues in G6PDH (Panel A) and 6PGDH (Panel B), respectively, mediated by AAPH-derived ROO^· (100 mM AAPH, 37 °C, 180 min). The data are presented as the average mass shifts due to the absence of specific standards to elucidate the nature of some of these species. The m/z + 0 data correspond to the unmodified parent Trp, Met and Tyr residues; the m/z + 4 (red) ions are assigned to Kyn formed on Trp oxidation; the m/z + 14 (accurately + 13.98, green) due to carbonyl formation; m/z + 16 (orange) due to the addition of a single oxygen atom (hydroxylation); m/z + 32 (blue) due to the addition of 2 oxygen atoms (NFK for Trp, sulfone for Met, and hydroperoxides or diols). The values correspond to mean data obtained from three different replicates carried out on different days. To facilitate data interpretation not all the mapped modifications (see Fig. 7) found in each protein are included; only those residues showing more than 1 product in G6PDH are included, whilst for 6PGDH only Trp and Tyr residues are included.