In enzymology, a tyrosine 2,3-aminomutase () is an enzyme that catalyzes the chemical reaction
Hence, this enzyme has one substrate, L-tyrosine, and one product, 3-amino-3-(4-hydroxyphenyl)propanoate.
This enzyme belongs to the family of isomerases, specifically those intramolecular transferases transferring amino groups. The systematic name of this enzyme class is L-tyrosine 2,3-aminomutase. This enzyme is also called tyrosine alpha,beta-mutase. This enzyme participates in tyrosine metabolism. It employs one cofactor, 5-methylene-3,5-dihydroimidazol-4-one (MIO) which is formed autocatalytic rearrangement of the internal tripeptide Ala-Ser-Gly.
As of late 2007, only one structure has been solved for this class of enzymes, with the PDB accession code .