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MetaCyc Enzyme: 6-pyruvoyl tetrahydrobiopterin synthase

Gene: PTS Accession Number: G-10203 (MetaCyc)

Species: Homo sapiens

Subunit composition of 6-pyruvoyl tetrahydrobiopterin synthase = [(PTS)3]2
         6-pyruvoyl tetrahydrobiopterin synthase trimer = (PTS)3
                 6-pyruvoyl tetrahydrobiopterin synthase monomer = PTS

Summary:
6-pyruvoyl tetrahydrobiopterin synthase, which catalyzes the conversion of 7,8-dihydroneopterin 3'-triphosphate to 6-pyruvoyl tetrahydropterin, was purified approximately 140,000-fold to apparent homogeneity from human liver [Takikawa86].

In addition, the PTS gene encoding the enzyme has been cloned from two cDNA libraries and expressed in Escherichia coli, and the recombinant proteins were purified [Ashida93, Burgisser94].

Cross-linking experiments and analysis by gel electrophoresis of the recombinant enzyme suggest that the native form is a homohexamer of 98 kDa composed of two trimeric subunits [Burgisser94]. This structure was confirmed when the crystal structure was solved at 2.3 Å [Nar94].

A transition metal binding site formed by three histidine residues in each subunit was shown to bind Zn2+ [Burgisser95].

Gene Citations: [Thony92]

Molecular Weight of Polypeptide: 16.386 kD (from nucleotide sequence), 17.0 kD (experimental) [Ashida93 ]

Molecular Weight of Multimer 6-pyruvoyl tetrahydrobiopterin synthase trimer: 50.0 kD (experimental) [Ashida93]

Molecular Weight of Multimer 6-pyruvoyl tetrahydrobiopterin synthase: 98.0 kD (experimental) [Burgisser94]

pI: 4.6 [Burgisser94]

Unification Links: ArrayExpress:Q03393 , Mint:MINT-1419639 , PhosphoSite:Q03393 , PhylomeDB:Q03393 , Pride:Q03393 , Protein Model Portal:Q03393 , SMR:Q03393 , String:9606.ENSP00000280362 , UniProt:Q03393

Relationship Links: Entrez-Nucleotide:PART-OF:M97655 , InterPro:IN-FAMILY:IPR007115 , InterPro:IN-FAMILY:IPR022469 , InterPro:IN-FAMILY:IPR022470 , Panther:IN-FAMILY:PTHR12589 , PDB:Structure:3I2B , Pfam:IN-FAMILY:PF01242 , Prosite:IN-FAMILY:PS00987 , Prosite:IN-FAMILY:PS00988

Gene-Reaction Schematic: ?

Credits:
Created 21-Sep-2007 by Caspi R , SRI International


Enzymatic reaction of: 6-pyruvoyl tetrahydrobiopterin synthase

EC Number: 4.2.3.12

7,8-dihydroneopterin 3'-triphosphate <=> 6-pyruvoyl tetrahydropterin + PPPi + H+

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the Enzyme Commission system.

The reaction is favored in the direction shown.

In Pathways: tetrahydrobiopterin biosynthesis I , tetrahydrobiopterin biosynthesis II

Summary:
Vmax of the purified recombinant protein was 0.84 μmol/min/mg protein [Ashida93]. Activity of the native purified enzyme was 8-fold lower.

Activators (Allosteric): Zn2+ [Burgisser95] , Mg2+ [Takikawa86]

Kinetic Parameters:

Substrate
Km (μM)
Citations
7,8-dihydroneopterin 3'-triphosphate
10.0
[Takikawa86]

pH(opt): 7.5 [Takikawa86]


References

Ashida93: Ashida A, Hatakeyama K, Kagamiyama H (1993). "cDNA cloning, expression in Escherichia coli and purification of human 6-pyruvoyl-tetrahydropterin synthase." Biochem Biophys Res Commun 195(3);1386-93. PMID: 8216273

Burgisser94: Burgisser DM, Thony B, Redweik U, Hunziker P, Heizmann CW, Blau N (1994). "Expression and characterization of recombinant human and rat liver 6-pyruvoyl tetrahydropterin synthase. Modified cysteine residues inhibit the enzyme activity." Eur J Biochem 219(1-2);497-502. PMID: 8307017

Burgisser95: Burgisser DM, Thony B, Redweik U, Hess D, Heizmann CW, Huber R, Nar H (1995). "6-Pyruvoyl tetrahydropterin synthase, an enzyme with a novel type of active site involving both zinc binding and an intersubunit catalytic triad motif; site-directed mutagenesis of the proposed active center, characterization of the metal binding site and modelling of substrate binding." J Mol Biol 253(2);358-69. PMID: 7563095

Nar94: Nar H, Huber R, Heizmann CW, Thony B, Burgisser D (1994). "Three-dimensional structure of 6-pyruvoyl tetrahydropterin synthase, an enzyme involved in tetrahydrobiopterin biosynthesis." EMBO J 13(6);1255-62. PMID: 8137809

Takikawa86: Takikawa S, Curtius HC, Redweik U, Leimbacher W, Ghisla S (1986). "Biosynthesis of tetrahydrobiopterin. Purification and characterization of 6-pyruvoyl-tetrahydropterin synthase from human liver." Eur J Biochem 161(2);295-302. PMID: 3536512

Thony92: Thony B, Leimbacher W, Burgisser D, Heizmann CW (1992). "Human 6-pyruvoyltetrahydropterin synthase: cDNA cloning and heterologous expression of the recombinant enzyme." Biochem Biophys Res Commun 189(3);1437-43. PMID: 1282802


Report Errors or Provide Feedback
Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
Page generated by SRI International Pathway Tools version 18.5 on Fri Nov 21, 2014, BIOCYC14B.