Here is the study report and website:
ncbi.nlm.nih.gov
Spontaneous Formation of Melanin from Dopamine in the Presence of Iron

Abstract
Parkinson’s disease is associated with degeneration of neuromelanin (NM)-containing substantia nigra dopamine (DA) neurons and subsequent decreases in striatal DA transmission. Dopamine spontaneously forms a melanin through a process called melanogenesis. This study examines conditions that promote/prevent DA melanogenesis. The kinetics, intermediates, and products of DA conversion to melanin in vitro, and DA melanogenesis under varying levels of Fe3+, pro-oxidants, and antioxidants were examined. Findings suggest that DA melanogenesis occurs spontaneously under physiologically-relevant conditions of oxidative stress and that NM may act as a marker of past exposure to oxidative stress.
Conclusions
In this study, we have characterized the spontaneous polymerization of DA into a melanin chemically similar to NM.
When aggregated and in the presence of an oxidative species, DA polymerizes into a melanin in a rapid, thermodynamically stable reaction. Melanization occurs in ex vivo conditions which is blocked by antioxidants. Although the effects of melanization in vivo are still not fully understood, the present results indicate that melanization requires pro-oxidants. Thus, melanization may be more relevant under conditions where iron has breached the blood brain barrier, such as ischemia, or increases in local H2O2, which has been implicated as a retrograde signaling molecule but is also present in intracellular compartments.

How soon this information is applied to PD research but this study puts the light on another possible advancement in PD research, in my opinion.
James, what are your thoughts? Do you know if anyone in the states is involved in this work?