Research Area: Neurological Disease Biological Activity: Levodopa (Sinemet) is an amino acid precursor of dopamine with antiparkinsonian properties. Dopamine is converted from levodopa (Sinemet) by DOPA decarboxylase and can cross the blood-brain barrier. When in the brain, levodopa is decarboxylated to dopamine and stimulates the dopaminergic receptors, thereby compensating for the depleted supply of endogenous dopamine seen in Parkinson’s disease. [1][2]