3-(Methoxy-d3)-L-tyrosine Monohydrate; 3-(Methoxy-d3)-4-hydroxyphenylalanine Monohydrate; 3-(Methoxy-d3)-DOPA Monohydrate; 3-(Methoxy-d3)-L-tyrosine Monohydrate; 3-O-(Methyl-d3)dopa Monohydrate; L-3-(Methoxy-d3)-4-hydroxy-|phenylalanine Monohydrate; L-3-O-(Methyl-d3)-DOPA Monohydrate; L-4-Hydroxy-3-(methoxy-d3)phenylalanine Monohydrate;

Labeled 3-O-Methyl-L-DOPA. 3-O-Methyl-L-DOPA is the major metabolite of L-DOPA via catechol O-methyltransferase (COMT). 3-Methoxy-L-tyrosine is neither a substrate for nor an inhibitor of L-amino acid decarboxylase activity. Inhibition of COMT enhances the anti-Parkinson activity of L-DOPA.