has role is protonated form of is tautomer of is enantiomer of L-dopa An optically active form of dopa having <small>L</small>-configuration. Used to treat the stiffness, tremors, spasms, and poor muscle control of Parkinson's disease L-tyrosine derivative plant growth retardant antiparkinson drug dopaminergic agent dopa D-dopa prodrug neurotoxin L-dopa zwitterion hapten allelochemical antidyskinesia agent L-dopa(1-) mouse metabolite plant metabolite human metabolite non-proteinogenic L-alpha-amino acid