Overview for MACiE Entry M0084

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General Information

EC Number: (A member of the Lyases, Carbon-oxygen lyases, Acting on phosphates)

Enzyme Name: 6-pyruvoyltetrahydropterin synthase

Biological Species: Rattus rattus (Rat)

Catalytic Chain UniprotKB Accession Codes:

  • P27213 - 6-pyruvoyl tetrahydrobiopterin synthase

Representative PDB Code: 1b66 - 6-PYRUVOYL TETRAHYDROPTERIN SYNTHASE (Resolution = 1.90 Å).

Catalytic CATH Codes:

  • 3.30.479.10 - Tetrahydropterin Synthase; Chain A
  • Unassigned Domain

Display structure information

Overall Reaction:

Image of 7,8-dihydroneopterin 3'-triphosphate

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Image of triphosphate

Image of 6-pyruvoyltetrahydropterin

7,8-dihydroneopterin 3'-triphosphate

Overall Comment: Step sequence 2-3 and 4-5 can occur in the order written or the converse order. I.e. 4-5 may occur before 2-3. Both zinc and magnesium are catalytically relevant metal ions, however the magnesium ion appears to only be involved in the binding of the triphosphate group and so is not annotated in this reaction.

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Stepwise Description of the Reaction

Step 1His89F, part of a Asp-His-Cys triad, deprotonates Cys42. The substrate deprotonates Glu133.
Step 2Cys42 deprotonates the substrate, initiating double bond rearrangement for which the now positively charged secondary amine acts as an electron sink.
Step 3Glu133 deprotonates the alcohol on the same carbon attacked by Cys42. This formed the keto-group and causes the double bond to deprotonate the Cys42.
Step 4Cys42 deprotonates the second carbon of the substrate carbon chain, which causes the formation of a new double bond and elimination of the diphosphate group.
Step 5The newly released diphosphate deprotonates the remaining alcohol group, which forms the ketol-form of the intermediate and causes the double bond to deprotonate Cys42.
Step 6Cys42 deprotonates His89F in an inferred step.

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Catalytic Residues Involved

Type Number Chain Location of Function
Cys 42 A Side Chain
Glu 133 A Side Chain
Asp 88 F Side Chain
His 89 F Side Chain

Metal Cofactors for M0084

Type Het group Number Chain
zinc ZN 401 x Overview
magnesium MG(not in PDB) 1 x Overview


  1. T. Ploom et al. (1999), J. Mol. Biol., 286, 851-860. Crystallographic and kinetic investigations on the mechanism of 6-pyruvoyl tetrahydropterin synthase.
    Medline: 10024455

Homologue information for M0084 (1b66)

CSA Homologues

MACiE Homologues (within the PDB)

MACiE Homologues (within UniprotKB/SwissProt)

Links to this entry in other databases

Link to EC-PDB-SUM Link to PDB-SUM Link to RCSB PDB Link to PDBe Link to CSA
Link to MetaCyc Link to KEGG Link to BRENDA Link to ExplorENZ
Link to EzCatDB

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6-pyruvoyltetrahydropterin synthase activity (molecular function)
tetrahydrobiopterin biosynthetic process (biological process)
metal ion binding (molecular function)