PRODUCTION OF M-METHYLTYROSINE AND P-HYDROXYMETHYLPHENYLALANINE FROM P-METHYLPHENYLALANINE BY PHENYLALANINE HYDROXYLASE

The metabolism of p-methylphenylalanine by phenylalanine hydroxylase has been studied, and three products have been found, m-methyltyrosine, p-methyl-m-hydroxyphenylalanine (p-methyl-m-tyrosine), and p-hydroxymethylphenylalanine. The production of m-methyltyrosine provides an example of the hydroxylation-in-duced migration of alkyl groups. The appearance of p-methyl-m-hydroxyphenyl-alanine suggests the migration of a hydroxyl group. The formation of p-hydroxy-methylphenylalanine demonstrates an unexpected side-chain hydroxylation by a pteridine-requiring enzyme normally involved in aromatic hydroxylation. © 1968.