tyrosine and tryptophan have been assayed spectrofluorometrically in postmortem human brain areas of patients with parkinson 's disease treated orally with or without 3,4-dihydroxyphenylalanine ( l-dopa ) plus the peripherally acting decarboxylase inhibitor benserazide .
C0013023
dihydroxyphenylalanine
C0023570
l-dopa