In enzymology, a 3-(hydroxyamino)phenol mutase (EC 5.4.4.3) is an enzyme that catalyzes the chemical reaction

3-hydroxyaminophenol ${\displaystyle \rightleftharpoons }$ aminohydroquinone

Hence, this enzyme has one substrate, 3-hydroxyaminophenol, and one product, aminohydroquinone.

This enzyme belongs to the family of isomerases, specifically those intramolecular transferases transferring hydroxy groups. The systematic name of this enzyme class is 3-(hydroxyamino)phenol hydroxymutase. Other names in common use include 3-hydroxylaminophenol mutase, and 3HAP mutase.

• Schenzle A, Lenke H, Spain JC, Knackmuss HJ (March 1999). "3-Hydroxylaminophenol mutase from Ralstonia eutropha JMP134 catalyzes a Bamberger rearrangement". Journal of Bacteriology. 181 (5): 1444–50. PMC 93532. PMID 10049374.