4-Chloro-DL-phenylalanine (S4586-GRP)

4-Chloro-DL-phenylalanine (Fenclonine, PCPA, CP-10188) is a selective and irreversible inhibitor of tryptophan hydroxylase, a rate-limiting enzyme in the biosynthesis of serotonin (5-HYDROXYTRYPTAMINE). 4-Chloro-DL-phenylalanine acts pharmacologically to deplete endogenous levels of serotonin.