Phenylalanine hydroxylase
| Phenylalanine hydroxylase | ||
|---|---|---|
| Properties of human protein | ||
| Mass / length primary structure | 452 amino acids | |
| Secondary to quaternary structure | Homodimer | |
| Cofactor | Fe 2+ , tetrahydrobiopterin | |
| Identifier | ||
| Gene name | PAH | |
| External IDs | ||
| Enzyme classification | ||
| EC, category | 1.14.16.1 , monooxygenase | |
| Substrate | L-phenylalanine + tetrahydrobiopterine + O 2 | |
| Products | L-tyrosine + 4a-hydroxytetrahydrobiopterin | |
| Occurrence | ||
| Homology family | Phenylalanine hydroxylase | |
| Parent taxon | Creature | |
The phenylalanine hydroxylase (PAH) is that enzyme , which in all living things the conversion of L- phenylalanine to tyrosine catalyzed . It is therefore indispensable for all eukaryotes for whom high concentrations of phenylalanine in the organism are harmful. PAH contains iron , although the iron is not bound to heme , and binds tetrahydrobiopterin as a cofactor . One oxygen atom from an O2 molecule is bound for the OH group in tyrosine and the other in tetrahydrobiopterine ( see mixed-functional monooxygenases ).
In humans, it occurs mainly in the cell fluid (the cytosol ) of liver cells . Mutations in the PAH - gene can be reduced or lacking activity of the enzyme and according to hyperphenylalaninaemia for up phenylketonuria lead.
Catalyzed reaction equilibrium
+ 
+ O 2 ⇔
⇔ 
+
Phenylalanine is oxidized to tyrosine and vice versa, tyrosine is reduced to phenylalanine.
Individual evidence
Web links
- Jennifer McDowall / Interpro: Protein Of The Month: Phenylalanine hydroxylase. (engl.)