the immediate da precursor , 3,4-dihydroxyphenylalanine ( l-dopa ) , and the metabolite , 3,4-dihydroxyphenylacetic acid ( dopac ) , were also detected at about 2.8 % and 17 % of da levels , respectively .
C0013023
dihydroxyphenylalanine
C0023570
l-dopa