Figure 3.

DJ-1 cannot remove early AGEs from peptides. (A) Purified synthetic peptide Ac-LESRHYA, (peptide 1) was allowed to react with equimolar MGO (1 mM) in 20 mM PBS at pH 7.3 for 3 h at 37 °C, and was then analyzed by LC-MS after subsequent or concurrent treatment with DJ-1. (B) Representative combined mass spectra (8.5–10 min) show a reduction in glycation only for concurrent treatments with DJ-1^WT. (C) Distribution of glycation products observed by LC-MS after DJ-1 treatment. Stacked bar graphs are plotted as mean ± standard deviation for each mass adduct. A nondirectional (two-tailed) one-way ANOVA using Dunnett’s multiple comparison test was used to determine statistically significant differences in total glycation compared to peptide 1 treated with MGO, p < 0.0001(****).