PDP1 and Alzheimer disease: Interestingly, under oxidative conditions, such as high H2O2 concentrations, the α-lipoic acid in α-ketoglutarate dehydrogenase, an enzyme similar to the PDH, the activity of which is also decreased in AD, is reversibly glutathionylated thereby protecting the sulfur-containing compound from modification e.g., by 4-hydroxynonenal (Applegate et al., 2008).