Aromatic amino acid hydroxylase (IPR001273)

Short name: ArAA_hydroxylase

Overlapping homologous superfamilies

Family relationships


Phenylalanine, tyrosine and tryptophan hydroxylases constitute a family of tetrahydrobiopterin-dependent aromatic amino acid hydroxylases, all of which are rate-limiting catalysts for important metabolic pathways [PMID: 3475690]. The proteins are structurally and functionally related, each containing iron, and catalysing ring hydroxylation of aromatic amino acids, using tetra-hydrobiopterin (BH4) as a substrate. All are regulated by phosphorylation at serines in their N-termini. It has been suggested that the proteins each contain a conserved C-terminal catalytic (C) domain and an unrelated N-terminal regulatory (R) domain. It is possible that the R domains arose from genes that were recruited from different sources to combine with the common gene for the catalytic core. Thus, by combining with the same C domain, the proteins acquired the unique regulatory properties of the separate R domains.

A variety of enzymes belong to this family that includes, phenylalanine-4-hydroxylase from Chromobacterium violaceum where it is copper-dependent; it is iron-dependent in Pseudomonas aeruginosa, phenylalanine-4-hydroxylase catalyzes the conversion of phenylalanine to tyrosine. In humans, deficiencies are the cause of phenylketonuria, the most common inborn error of amino acid metabolism [PMID: 9406548], tryptophan 5-hydroxylase catalyzes the rate-limiting step in serotonin biosynthesis: the conversion of tryptophan to 3-hydroxy-anthranilate and tyrosine 3-hydroxylase catalyzes the rate limiting step in catecholamine biosynthesis: the conversion of tyrosine to 3,4-dihydroxy-L-phenylalanine.

GO terms

Biological Process

GO:0009072 aromatic amino acid family metabolic process
GO:0055114 oxidation-reduction process

Molecular Function

GO:0005506 iron ion binding
GO:0004497 monooxygenase activity

Cellular Component

No terms assigned in this category.

Contributing signatures

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