Parkinson disease (PD) is a multifactorial neurodegenerative condition characterized by the progressive loss of dopaminergic neurons. Several hypothesis have been proposed in the literature to describe the mechanisms that lead to neurodegeneration in PD. This study is focus on the ossidative stress associated to the redox chemistry of dopamine (DA). The rational in this choice is that DA oxidation may reasonably account for the specificity observed for dopaminergic neuron degeneration in PD. The redox reactions that specifically involve DA may be either enzymatic or spontaneous and several different pathways have been identified for the oxidation of DA. The self-oxidations of DA and DOPA (3,4-dihydroxyphenylalanine) generate superoxide anions and reactive quinones such as DA quinone and DOPAquinone. These quinones can easily cyclize to aminochrome and DOPAchrome and then eventually polymerize to form neuromelanin. Although the oxidation of DA and DOPA lead to the formation of toxic ROS, the main cytotoxic species which could potentially explain the specific damage to dopaminergic neurons remain the highly reactive quinone species DAQ that have many potential protein targets for chemical modifications. The strategy we propose stems from the genetic research on the proteins linked to PD. The identification of several proteins whose functions are affected by mutations that are associated to familiar PD triggered the hypothesis that late onset idiopathic forms of PD may derive from similar functional effects induced by chemical modifications produced by DAQ on the very same proteins, leading to the manifestation of

the pathology.