Overview for MACiE Entry M0134
EC Number: 220.127.116.11 (A member of the Oxidoreductases, Acting on paired donors, with O2 as oxidant and incorporation or reduction of oxygen. The oxygen incorporated need not be derived from O2, With reduced pteridine as one donor, and incorporation of one atom of oxygen into the other donor)
Enzyme Name: tyrosine 3-monooxygenase
Biological Species: Rattus norvegicus (Rat)
Catalytic Chain UniprotKB Accession Codes:
- P04177 - Tyrosine 3-monooxygenase
Representative PDB Code: 2toh - TYROSINE HYDROXYLASE CATALYTIC AND TETRAMERIZATION DOMAINS FROM RAT (Resolution = 2.30 Å).
Catalytic CATH Codes:
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This reaction is irreversible.
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Stepwise Description of the Reaction
|Step 1||The Fe(II) centre donates a single electron to the dioxygen molecule in a homolytic addition.|
|Step 2||The bound dioxygen radical initiates an electrophilic addition to the aromatic tetrahydrobiopterin which causes a single electron to be transferred back to the Fe(III) centre.|
|Step 3||The Fe(II) centre donates an electron pair to the oxygen bound directly to the Fe ion, eliminating the 4a-hydroxytetrahydrobiopterin product by cleaving the peroxo bond. The product undergoes an internal proton transfer to generate the final state.|
|Step 4||Tyrosine initiates an electrophilic addition to the bound iron-bound oxo group, causing the iron centre to accept two electrons.|
|Step 5||In an NIH shift, the alkoxide group forms a ketone group, initiating an internal hydride transfer.|
|Step 6||The intermediate undergoes a keto-enol tautomerisation forming the 3,4-dihydroxy-L-phenylalanine tautomer of the product.|
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Catalytic Residues Involved
||Location of Function
Metal Cofactors for M0134
- P. F. Fitzpatrick (2003), Biochemistry, 42, 14083-14091. Mechanism of aromatic amino acid hydroxylation.
- H. R. Ellis et al. (2000), Biochemistry, 39, 4174-4181. Mutation of serine 395 of tyrosine hydroxylase decouples oxygen-oxygen bond cleavage and tyrosine hydroxylation.
Homologue information for M0134 (2toh)
MACiE Homologues (within the PDB)
MACiE Homologues (within UniprotKB/SwissProt)
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