Tyrosine
An amino acid, one of the 20 building blocks of protein.
A nonessential amino acid, tyrosine is produced from another amino acid, phenylalanine.
Deficiency of the enzyme phenylalanine hydroxylase that catalyzes this reaction causes the genetic disease called phenylketonuria (PKU).
Tyrosine is a precursor of thyroid hormones, catecholamines, and melanin.
Symbol: Tyr