Parkinson’s etiology has long been associated with redox imbalance and oxidative stress in dopaminergic neurons. The catecholaldehyde hypothesis suggests that DOPAL, an obligate product of dopamine catabolism, is a central nexus in a network of pathways leading to disease-state neurodegeneration, owing to its toxicity and potent ability to oligomerize alpha synuclein, the main component of protein aggregates in Lewy bodies. In this work we examine the connection between reactive oxygen species and DOPAL autoxidation. We show that superoxide propagates a chain reaction oxidation, and that this reaction is dramatically inhibited by superoxide dismutase. Moreover, superoxide dismutase prevents DOPAL from forming dicatechol pyrrole adducts with lysine and from covalently crosslinking alpha synuclein. Given that superoxide is the main radical byproduct of impaired cellular respiration, our results provide a plausible mechanistic link between mitochondrial dysfunction and synuclein aggregation in dopaminergic neurons.