Abstract
A simple radioenzymatic method for the determination of DOPA is described. The method is based on the conversion of DOPA to 3-O-[methyl-3H]DOPA by catechol-O-methyltransferase in the presence of S-adenosyl-[methyl-3H]methionine and purification of the labelled product by Sephadex G10 and Dowex 50 W × 4 ion exchange resin. The method has been applied to the assay of endogenous DOPA in different brain areas and to measuring DOPA accumulation after inhibition of aromatic amino acid DOPA decarboxylase.