6) Main uses of protein hydrolysates in clinical nutrition
A. Phenylketonuria (PKU)
1. Phenylketonuria, or hyperphenyl-alaninemia, is one of the most well known disorders of
amino acid metabolism
2. It is caused by the autosomal recessive deficiency or absence of the hepatic enzyme
phenylalanine hydroxylase, which converts phenylalanine to tyrosine
3. Lack of this enzyme leads to phenylpyruvic acid accumulation in the blood
4. When dietary treatment with phenylalanine restriction is started early, the child can achieve
close to normal development
5. The dietary management of PKU patients
① A mixture of free amino acids fortified with carbohydrates, vitamins and minerals
② Infant formula which has a similar nutritional composition to normal infant formula
milks using phenylalanine-free enzymatic protein hydrolysates
6. Phenylalanine-free protein hydrolysates or protein hydrolysates with low levels of this
amino acid have been used for treatment of pheylketonuric infants
7. The development of protein hydrolysates for patients with PKU in post-hydrolysis
procedures
to remove phenylalanine
① The treatment by activated carbon
② The use of ionic exchange resins