although alpha- ( mono- and difluoromethyl ) -5-hydroxytryptophans are potent irreversible inhibitors of aromatic amino acid decarboxylase ( equipotent to alpha-difluoromethyl-dopa ) , only alpha- ( monofluoromethyl ) tryptophan affects the level of serotonin in vivo ( small decrease ) , alpha- ( difluoromethyl ) tryptophan being a very poor substrate of the activating ( or helper ) enzyme , tryptophan hydroxylase .
C0000578
5-hydroxytryptophans
C0041249
tryptophan