Increased S-nitrosylation of parkin and p53 levels in postmortem human brains from Parkinson’s disease (PD) and Incidental Lewy body disease (ILBD). A, Levels of SNO-parkin, total parkin, p53, and actin examined by biotin-switch and western blot in lysates prepared from unaffected control brains (ctrl) and brains with PD and ILBD. B, Ratios of SNO-parkin relative to total parkin were calculated to indicate the extent of parkin S-nitrosylation in ctrl, PD and ILBD samples. Values are mean + SEM of samples from 2 control, 5 PD and 2 ILBD human brains; * p < 0.05. C, p53 levels are quantified and normalized to actin for ctrl, PD and ILBD brains. Values are mean + SEM; * p < 0.01. D, Ratios of SNO-parkin/parkin and p53/actin were plotted for each sample. The two values are positively correlated with a Pearson correlation coefficient of 0.682 and p < 0.05.