Fig. 5

Parkin alters glutathione metabolism in human brain and affects the activity of redox state-dependent enzymes in mice. a HPLC-based quantification of reduced glutathione (GSH), oxidized glutathione (GSSG), the ratio of GSH:GSSG, and total glutathione (GSH + 2GSSG) in cortex homogenates from age-matched human control and PRKN-deficient autosomal recessive PD (ARPD) cases; b, c Western blot analysis of glutathione reductase (GR) protein levels, as separated by SDS/PAGE (reducing conditions) c its quantification by densitometry (normalized to actin) and d GR activity measured in cortex homogenates from the same 8 cases. e Western blot results of aconitase-2 (Aco2), mitochondrial creatine kinase (mtCK), and parkin expression in membrane extracts of the four control and four ARPD cortices (as in b–c). f, g Quantification of relative expression levels of Aco2 and mtCK (shown in e). h Protein levels of murine Aco2, mtCK, Tom20 and VDAC in mitochondrial extracts from wild-type (WT) and prkn^−/− brains of 12 month-old mice, as shown by Western blotting. i Aco2 and j mtCK activities, as measured in freshly isolated mitochondria from WT and prkn^−/− brains with or without exogenous treatment of 4 μM H₂O₂. Data in a-b are plotted as mean values (nmol/µg total protein) ± SEM. Significance was determined using an unpaired Student T-test (a, c, d, f–h) and 2-way ANOVA with Tukey’s post-hoc analysis (i, j), where *p ≤ 0.05, **p ≤ 0.01, and ***p ≤ 0.001