D-DOPA

-DOPA (-3,4-dihydroxyphenylalanine; dextrodopa) is similar to -DOPA (levodopa), but with opposite chirality. Levo- and dextro- rotation refer to a molecule's ability to rotate planes of polarized light in one or the other direction. Whereas -DOPA is moderately effective in the treatment of Parkinson's disease (PD) and dopamine-responsive dystonia (DRD) by stimulating the production of dopamine in the brain, -DOPA is biologically inactive.