The hydroxylation of phenylalanine and antipyrine in phenylpyruvic oligophrenia.

In normal individuals the major portion of ingested phenylalanine is converted into tyrosine. In the disease phenylpyruvic oligophrenia, however, ingested phenylalanine is converted mainly into phenylpyruvic and phenyllactic acids (l), which are excreted in the urine. This phenomenon has been ascribed to the inability of the body to convert phenylalanine to tyrosine (2) and a consequent shunting of phenylalanine through metabolic pathways which are normally of minor significance. The experiments presented here demonstrate that the failure of phenylpyruvic oligophrenic individuals (phenylketonurics) to hydroxylate phenylalanine is not absolute; they can form tyrosine to a small but definite degree. In these individuals the hydroxylation of certain other aromatic compounds is apparently unaffected.