phenylalanine-4-hydroxylase; phenylalanine-4-monooxygenase (PAH)
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Function
- amino-acid degradation, L-phenylalanine degradation
- acetoacetate & fumarate from L-phenylalanine: step 1/6
L-phenylalanine + tetrahydrobiopterin + O2
<-->
L-tyrosine + 4a-hydroxytetrahydrobiopterin
Cofactor: Fe+2 ion
Structure
- homodimer
- belongs to the biopterin-dependent aromatic amino acid
- hydroxylase family
- contains 1 ACT domain
- N-terminal region of PAH is thought to contain allosteric binding sites for phenylalanine & to constitute an "inhibitory" domain that regulates the activity of a catalytic domain in the C-terminal portion of the enzyme
Pathology
- defects in PAH are the cause of hyperphenylalaninemia & phenylketonuria
Polymorphism
- Glu-274 variant occurs on approximately 4% of African-American PAH alleles; enzyme activity of this variant is normal
Laboratory
More general terms
References
- ↑ Principles of Biochemistry 6th ed., White, Handler, Smith, Hill, & Lehman (eds.) McGraw-Hill, NY 1978, pg 689
- ↑ UniProt http://www.uniprot.org/uniprot/P00439.html
- ↑ PAHdb; Phenylalanine hydroxylase locus knowledgebase http://www.pahdb.mcgill.ca/
- ↑ GeneReviews https://www.genecards.org/cgi-bin/carddisp.pl?gene=PAH
- ↑ Wikipedia; Phenylalanine hydroxylase entry http://en.wikipedia.org/wiki/Phenylalanine_hydroxylase