The involvement of mitochondria in Alzheimer's Disease has been known for many years with reduced cytochrome c oxidase (Complex IV) assembly and activity considered as an early event in the disease, and reduced cytochrome c oxidase activity has been reported in platelets from patients with Alzheimer's Disease.
Recent studies begin to explain mitochondrial involvement. The Alzheimer's amyloid precursor protein has now been localized to mitochondria as has the toxic amyloid beta peptide. The binding site for amyloid beta has been identified as alcohol dehydrogenase in the matrix space of the organelle.
This enzyme can metabolize aldehydes and if the function is impaired could be involved in generation of oxidative radicals and a consequent cell death. Another mitochondrial protein implicated in Alzheimer's Disease is pyruvate dehydrogenase.