Sentence Examples

  • Phenylketonuria-A condition caused by a genetic error of the body's metabolism, characterized by the absence of phenylalanine hydroxylase (an enzyme that converts phenylalanine into tyrosine).
  • The hairbulb pigmentation test is used to identify carriers by incubating a piece of the person's hair in a solution of tyrosine, a substance in food which the body uses to make melanin.
  • It measures the rate at which hair converts the amino acid tyrosine into another chemical (3,4-dihydroxyphenylalanine, or DOPA), which is then made into pigment.
  • Typical diets prescribed for PKU patients provide very small amounts of phenylalanine and higher quantities of other amino acids, including tyrosine.
  • Another, more accurate test procedure for PKU measures the ratio (comparison) of the amount of phenylalanine to the amount of tyrosine in the blood.