Aromatic amino acid hydroxylase, C-terminal (IPR019774)

Short name: Aromatic-AA_hydroxylase_C

Overlapping homologous superfamilies

Domain relationships



Hydroxylation of the aromatic amino acids phenylalanine, tyrosine and tryptophan is carried out by a family of non-heme iron and tetrahydrobiopterin (BH4) dependent enzymes: the aromatic amino acid hydroxylase [PMID: 3475690]. Theseenzymes are structurally and functionally similar. The eukaryotic forms include a regulatory N-terminal domain, a catalytic domain and a C-terminal oligomerization motif. The eukaryotic enzymes are all homotetramers [PMID: 14640675, PMID: 15537351].

Three-dimensional structures have been determined for the three types of enzymes. The iron atom is bound to three amino acid residues, two close histidine and a more distant acidic residue. This arrangement of ligands has been observed in a number of metalloproteins with divergent function [PMID: 11718561].

Enzymes that belong to the aromatic amino acid hydroxylase family are listed below:

  • Phenylalanine-4-hydroxylase (EC: (PAH). Catalyzes the conversion of phenylalanine to tyrosine. In humans, deficiencies [PMID: 8594560] of PAH are the cause of phenylketonuria, the most common inborn error of amino acid metabolism. In the bacteria Chromobacterium violaceum [PMID: 1655752], PAH is copper-dependent; it is iron-dependent in Pseudomonas aeruginosa [PMID: 8108417].
  • Tyrosine 3-hydroxylase (EC: (TYH). Catalyzes the rate limiting step in catecholamine biosynthesis: the conversion of tyrosine to 3,4- dihydroxy-L-phenylalanine.
  • Tryptophan 5-hydroxylase (EC: (TRH). Catalyzes the rate-limiting step in serotonin biosynthesis: the conversion of tryptophan to 3-hydroxy- anthranilate.

This entry represents a domain containing the catalytic domain and the coiled-coil C-terminal oligomerization motif.

GO terms

Biological Process

GO:0055114 oxidation-reduction process

Molecular Function

GO:0016714 oxidoreductase activity, acting on paired donors, with incorporation or reduction of molecular oxygen, reduced pteridine as one donor, and incorporation of one atom of oxygen

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
PROSITE profiles