about the formation and metabolism of beta protein:

https://www.google.com/search?q=C.+P...sm=93&ie=UTF-8

But we were unable to find a small molecule that worked in vivo to prevent the plaques and tangles that are seen in the histopathology of the Alzheimer brain. Alpha, beta and gamma secretase enzyme cleavage of the transmembrane precursor protein, is thought to produce a protein that misfolds, and clumps together causing neuronal death, basically choking the supply of nutrients and other factors to cortical neurons.

If the same thing is happening with alpha-synuclein to produce Lewy bodies which are just a marker of damage done via the inhibitory effect of alpha synuclein on complex 1 activity of mitochondrial respiratory chain(see Wikipedia for a detailed explanation), and the eventual death of motor neurons, then we are on the right track, to explain the root cause of "synucleopathy", and thus parkinsonism. At the present time this is all just theory, but at least we have a theory to build on, one which may not cure PD but help to prevent it.