Homologous Superfamily

Aromatic amino acid monoxygenase, C-terminal domain superfamily (IPR036329)

Short name: Aro-AA_hydroxylase_C_sf

Overlapping entries


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.

Contributing signatures

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