Biopterin_H | |||||||||
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crystal structure of ternary complex of the catalytic domain of human phenylalanine hydroxylase (Fe(II)) complexed with tetrahydrobiopterin and norleucine
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Identifiers | |||||||||
Symbol | Biopterin_H | ||||||||
Pfam | PF00351 | ||||||||
InterPro | IPR019774 | ||||||||
PROSITE | PDOC00316 | ||||||||
SCOP | 1toh | ||||||||
SUPERFAMILY | 1toh | ||||||||
CDD | cd00361 | ||||||||
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Available protein structures: | |
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Pfam | structures |
PDB | RCSB PDB; PDBe; PDBj |
PDBsum | structure summary |
Biopterin-dependent aromatic amino acid hydroxylases (AAAH) are a family of aromatic amino acid hydroxylase enzymes which includes phenylalanine 4-hydroxylase (EC 1.14.16.1), tyrosine 3-hydroxylase (EC 1.14.16.2), and tryptophan 5-hydroxylase (EC 1.14.16.4). These enzymes primarily hydroxylate the amino acids L-phenylalanine, L-tyrosine, and L-tryptophan, respectively.
The AAAH enzymes are functionally and structurally related proteins which act as rate-limiting catalysts for important metabolic pathways. Each AAAH enzyme contains iron and catalyzes the ring hydroxylation of aromatic amino acids using tetrahydrobiopterin (BH4) as a substrate. The AAAH enzymes are regulated by phosphorylation at serines in their N-termini.
In humans, phenylalanine hydroxylase deficiency can cause phenylketonuria, the most common inborn error of amino acid metabolism. Phenylalanine hydroxylase catalyzes the conversion of L-phenylalanine to L-tyrosine. Tyrosine hydroxylase catalyzes the rate-limiting step in catecholamine biosynthesis: the conversion of L-tyrosine to L-DOPA. Similarly, tryptophan hydroxylase catalyzes the rate-limiting step in serotonin biosynthesis: the conversion of L-tryptophan to 5-hydroxy-L-tryptophan.