Phenylalanine-4-hydroxylase, tetrameric form (IPR005961)

Short name: Phe-4-hydroxylase_tetra

Overlapping homologous superfamilies

Family relationships


This entry represents the large, tetrameric form of phenylalanine-4-hydroxylase (PAH; EC:, as found in metazoans. PAH irreversibly converts phenylalanine to tyrosine, and is known to be the rate-limiting step in phenylalanine catabolism in some systems. It is closely related to metazoan tyrosine 3-monooxygenase and tryptophan 5-monoxygenase, and more distantly to monomeric phenylalanine-4-hydroxylases of some Gram-negative bacteria. The member of this family from Drosophila has been described as having both phenylalanine-4-hydroxylase and tryptophan 5-monoxygenase activity [PMID: 1371286]. However, a Drosophila member of the tryptophan 5-monoxygenase clade has subsequently been discovered.

A deficiency in PAH can lead to phenylketonuria (PKU), an autosomal recessive genetic disorder characterised by an inability to metabolise phenylalanine, resulting in elevated Phe levels in the bloodstream that can lead to mental retardation if left untreated [PMID: 16253218].

GO terms

Biological Process

GO:0006559 L-phenylalanine catabolic process
GO:0055114 oxidation-reduction process

Molecular Function

GO:0004505 phenylalanine 4-monooxygenase activity

Cellular Component

No terms assigned in this category.

Contributing signatures

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