Free amino acids were determined quantitatively in saliva of 23 children with phenylketonuria (male = 11, female = 12) (ages 6-17 years). Saliva was deproteinised by adding an equal volume of 5% sulphosalicylic acid and the amino acids were separated by ion exchange column chromatography.
Results: The comparison of the amino acid concentrations in saliva of phenylketonuric children with healthy children (male = 34, female = 31) (ages 6-13 years) showed, that vast majority of amino acids - taurine, serine, glutamine, glycine, alanine, citrulline, a-aminobutyric acid, valine, isoleucine, leucine, tyrosine, phenylalanine, ornithine, lysine, delta-aminovaleric acid - were excreted significantly lower in saliva of phenylketonuric children.