Brain peroxidase and catalase in Parkinson disease.

Peroxidase and catalase activities were determined in various regions of parkinsonian brains and control brains from patients with nonneurological diseases. The highest peroxidase activity was localized in the substantia nigra of the normal brain. In Parkinson disease, the peroxidase activity was decreased in the substantia nigra, caudate and putamen. Catalase activity was also reduced in the substantia nigra and putamen of the parkinsonian brain. These enzyme changes may be causally related to the degeneration and depigmentation of the substantia nigra neurons in Parkinson disease.