By contrast, a zinc deficiency is associated with Parkinson's disease. Levels of zinc in the cerebrospinal fluid of victims are substantially lower than those without Parkinson's. The enzyme superoxide dismutase contains zinc as an essential component. It is normally present in high concentrations in the substantia nigra where it scavenges free radicals. It catalyzes the dismutation of superoxide anions to hydrogen peroxide and oxygen thus exerting a neuroprotective effect.
Zinc supplementation produces significant increases in superoxide dismutase activity.
Normal metabolism of dopamine results in production of peroxide, superoxide, and hydroxyl radicals, all reactive oxygen species. It also results in the formation of reactive quinones similar to those found in environmental toxins that can damage cellular macromolecules covalently. This suggests a more direct role of dopamine in neurodegeneration. This process is facilitated by iron and manganese ions, further implicating those metals in the pathophysiology of this disease. Iron in the basal ganglia in Parkinson's disease.