The present work was carried out, using phenylalanine labelled with carbon-14, to examine whether phenylalanine is a precursor of tyrosine.

Aspartame a methyl ester L-aspartylphenylalanine, is a widely used sweetener. The intake of aspartame was studied in 51 adults 23 of whom were carriers for phenylketonuria (PKU). The study was ...