Parkinson's disease (PD) is predominantly a movement disorder resulting from degeneration of dopaminergic neurons in the substantia nigra. The cause of the disease is unknown, but substantial evidence suggests that the aggregation of alpha-synuclein is a critical step in the etiology of PD. Alpha-Synuclein is an abundant brain protein of 140 residues that is present in high concentration at presynaptic terminals and is found in both soluble and membrane-associated fractions of the brain. Several possible functions have been suggested, and they appear to be involved in vesicle release and trafficking. In vitro incubation in the presence of 0.1M NaCl with agitation can form fibrilous structure.