Among the non-o-dihydroxy conipounds tested, 4- fluorophenylalanine was the most potent inhibitor. 4- Fluorophenylalanine was reported to act as a substrate for PA hydroxylase'O and to inhibit the hydroxylation of phenylalanine competitively. Our studies showed that a-methyl derivatives of DOP-4 and 4-fluorophenyl- alanine were considerably less active as inhibitors than their respective parent compounds. Furthermore, 4- fluorocinnamic, -phenylarctic, ...
