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Literature summary for 3.5.4.25 extracted from

  • Ritz, H.; Schramek, N.; Bracher, A.; Herz, S.; Eisenreich, W.; Richter, G.; Bacher, A.
    Biosynthesis of riboflavin: studies on the mechanism of GTP cyclohydrolase II (2001), J. Biol. Chem., 276, 22273-22277.
    View publication on PubMed
Search for more literature for 3.5.4.25

Inhibitors

Inhibitors Comment Organism Structure
diphosphate competitive Escherichia coli
phosphate partial uncompetitive at low concentration, competitive at concentrations above 6 mM Escherichia coli

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
additional information
-
 additional information kinetics, cooperative reaction with a Hill coefficient of 1.3 Escherichia coli

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
GTP + 3 H2O Escherichia coli first committed step in the biosynthesis of riboflavin, overview formate + 2,5-diamino-6-beta-ribosylamino-4(3H)-pyrimidinone 5'-phosphate + diphosphate
-
 ?

Organism

Organism UniProt Comment Textmining
Escherichia coli
-
-
-

Reaction

Reaction Comment Organism Reaction ID
GTP + 4 H2O = formate + 2,5-diamino-6-hydroxy-4-(5-phospho-D-ribosylamino)pyrimidine + 2 phosphate 2 C-N bonds are hydrolysed, releasing formate, with simultaneous removal of the terminal diphosphate, reaction mechanism Escherichia coli
a

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
GTP + 3 H2O first committed step in the biosynthesis of riboflavin, overview Escherichia coli formate + 2,5-diamino-6-beta-ribosylamino-4(3H)-pyrimidinone 5'-phosphate + diphosphate
-
 ?
GTP + 3 H2O
-
 Escherichia coli formate + 2,5-diamino-6-beta-ribosylamino-4(3H)-pyrimidinone 5'-phosphate + diphosphate spontaneous isomerization into the alpha-isomer, also the product can easily spontaneously decompose under formation of 2,4,5-triamino-4-(3H)-pyrimidone ?

Synonyms

Synonyms Comment Organism
GTP-8-formylhydrolase
-
 Escherichia coli
guanosine triphosphate cyclohydrolase II
-
 Escherichia coli

Temperature Optimum [°C]

Temperature Optimum [°C] Temperature Optimum Maximum [°C] Comment Organism
37
-
 assay at Escherichia coli

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
8.5
-
 assay at Escherichia coli

Ki Value [mM]

Ki Value [mM] Ki Value maximum [mM] Inhibitor Comment Organism Structure
0.024
-
 diphosphate pH 8.5, 37°C Escherichia coli