Tyrosine is an amino acid found in proteins. In mammals, tyrosine is an non-essential amino acid, meaning it does not need to be present in the diet. Tyrosine's hydroxyl group is a target for phosphorylation in some proteins.

Tyrosine's benzene-ring side chain classifies it as an aromatic amino acid. The aromatic amino acids, like most compounds carrying conjugated rings, exhibit strong absorption of light in the near-ultraviolet region of the spectrum (Figure 5.6). This absorption is frequently used for the analytical detection of proteins. Tyrosine and tryptophan have some hydrophobic character, but it is tempered by the polar groups in their side chains. In addition, tyrosine can ionize at high pH.

One Letter Code	Three Letter Code	Molecular Wt. (Daltons)	Genetic Code Codons
Y	TYR	163.18	UAU, UAC

1. Phenylalanine, Tyrosine, and Tryptophan Biosynthesis

2. Tyrosine Metabolism