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Literature summary for 3.5.4.29 extracted from

  • Graham, D.E.; Xu, H.; White, R.H.
    A member of a new class of GTP cyclohydrolases produces formylaminopyrimidine nucleotide monophosphates (2002), Biochemistry, 41, 15074-15084.
    View publication on PubMed

Activating Compound

Activating Compound Comment Organism Structure
NH4+ activation of GTP cyclohydrolase activity, maximal activity at 50 mM Methanocaldococcus jannaschii

Cloned(Commentary)

Cloned (Comment) Organism
expression in Escherichia coli Methanocaldococcus jannaschii

Protein Variants

Protein Variants Comment Organism
H136Q approx. 7 and 15% of wild-type GTP cyclohydrolase and diphosphate phosphohydrolase activity, respectively Methanocaldococcus jannaschii

Inhibitors

Inhibitors Comment Organism Structure
8-azido-GTP 0.6 mM, 91% inhibition of GTP cyclohydrolase activity, 0.3 mM, 53% inhibition of diphosphate phosphohydrolase activity Methanocaldococcus jannaschii
8-bromo-GTP 0.1 mM, 50% inhibition of GTP cyclohydrolase activity, 0.1 mM, 64% inhibition of diphosphate phosphohydrolase activity Methanocaldococcus jannaschii
alpha,beta-methylene-GTP 0.06 mM, 80% inhibition of GTP cyclohydrolase activity, 0.6 mM, 33% inhibition of diphosphate phosphohydrolase activity Methanocaldococcus jannaschii
beta,gamma-methylene-GTP 0.6 mM, 34% inhibition of GTP cyclohydrolase activity Methanocaldococcus jannaschii
diphosphate inhibition of diphosphate phosphohydrolase activity at high concentrations Methanocaldococcus jannaschii
GDP more than 40% inhibition of GTP cyclohydrolase activity Methanocaldococcus jannaschii
GMP more than 40% inhibition of GTP cyclohydrolase activity Methanocaldococcus jannaschii
GTP-gamma-S 0.6 mM, 80% inhibition of GTP cyclohydrolase activity Methanocaldococcus jannaschii
IMP 0.6 mM, 25% inhibition of GTP cyclohydrolase activity Methanocaldococcus jannaschii
methylene diphosphate 0.6 mM, 40% inhibition of GTP cyclohydrolase activity, 0.6 mM, 56% inhibition of diphosphate phosphohydrolase activity Methanocaldococcus jannaschii
NaF 0.06 mM, 55% inhibition of diphosphate phosphohydrolase activity Methanocaldococcus jannaschii
phosphate 0.6 mM, 25% inhibition of GTP cyclohydrolase activity Methanocaldococcus jannaschii
tripolyphosphate 0.6 mM, 50% inhibition of GTP cyclohydrolase activity, 0.05 mM, 52% inhibition of diphosphate phosphohydrolase activity Methanocaldococcus jannaschii
XTP 0.6 mM, 52% inhibition of GTP cyclohydrolase activity Methanocaldococcus jannaschii

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
0.054
-
GTP pH 8.0, 70°C, GTP cyclohydrolase activity Methanocaldococcus jannaschii
0.063
-
GTP pH 8.0, 70°C, diphosphate phosphohydrolase activity Methanocaldococcus jannaschii

Metals/Ions

Metals/Ions Comment Organism Structure
CoCl2 45% of Mg2+ diphosphate phosphohydrolase activation Methanocaldococcus jannaschii
K+ activation of GTP cyclohydrolase activity Methanocaldococcus jannaschii
Mg2+ required for cyclohydrolase activity, maximal activity at 4 mM, no other metal supports full activity, maximal diphosphate phosphohydrolase activity in the presence of 5 mM MgCl2 Methanocaldococcus jannaschii
Mn2+ 7% of Mg2+ activation, 8% of Mg2+ diphosphate phosphohydrolase activation Methanocaldococcus jannaschii
Zn(OAc)2 21% of Mg2+ diphosphate phosphohydrolase activation Methanocaldococcus jannaschii

Molecular Weight [Da]

Molecular Weight [Da] Molecular Weight Maximum [Da] Comment Organism
30275
-
3 * 30275, deduced from nucleotide sequence Methanocaldococcus jannaschii
30359
-
3 * 30359, MALDI-TOF mass spectrometry Methanocaldococcus jannaschii
37000
-
3 * 37000, SDS-PAGE Methanocaldococcus jannaschii
98300
-
gel filtration Methanocaldococcus jannaschii

Organism

Organism UniProt Comment Textmining
Methanocaldococcus jannaschii Q57609 hyperthermophilic euryarcheon
-

Purification (Commentary)

Purification (Comment) Organism
heating, streptomycin, Mono Q, Sephacryl, recombinant enzyme Methanocaldococcus jannaschii

Reaction

Reaction Comment Organism Reaction ID
GTP + 3 H2O = 2-amino-5-formylamino-6-(5-phospho-D-ribosylamino)pyrimidin-4(3H)-one + 2 phosphate although phosphate is the product of the enzymes phosphohydrolase activity, diphosphate is a likely intermediate Methanocaldococcus jannaschii

Specific Activity [micromol/min/mg]

Specific Activity Minimum [µmol/min/mg] Specific Activity Maximum [µmol/min/mg] Comment Organism
0.39
-
recombinant enzyme Methanocaldococcus jannaschii

Storage Stability

Storage Stability Organism
4°C, 50 mM TAPS/KOH, pH 8.0, 150 mM KCl, 9 weeks, 20% loss of activity Methanocaldococcus jannaschii

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
beta,gamma-methylene-GTP + H2O
-
Methanocaldococcus jannaschii 2-amino-5-formylamino-6-hydroxy-4-(5-phosphoribosylamino)-pyrimidine + methyl phosphonate
-
?
dGTP + H2O
-
Methanocaldococcus jannaschii 2-amino-5-formylamino-6-hydroxy-4-(deoxy-5-phosphoribosylamino)-pyrimidine + phosphate
-
?
diphosphate + H2O
-
Methanocaldococcus jannaschii 2 phosphate
-
?
GTP + H2O
-
Methanocaldococcus jannaschii 2-amino-5-formylamino-6-hydroxy-4-(5-phosphoribosylamino)-pyrimidine + phosphate enzyme has diphosphate phosphohydrolase and GTP cyclohydrolase activities, no activity with 8-bromo-GTP, 8-azido-GTP, alpha,beta-methylene-GTP, ATP, GDP, GMP and XTP ?
GTP-gamma-S + H2O
-
Methanocaldococcus jannaschii 2-amino-5-formylamino-6-hydroxy-4-(5-phosphoribosylamino)-pyrimidine + ?
-
?

Subunits

Subunits Comment Organism
trimer 3 * 37000, SDS-PAGE Methanocaldococcus jannaschii
trimer 3 * 30275, deduced from nucleotide sequence Methanocaldococcus jannaschii
trimer 3 * 30359, MALDI-TOF mass spectrometry Methanocaldococcus jannaschii

Temperature Optimum [°C]

Temperature Optimum [°C] Temperature Optimum Maximum [°C] Comment Organism
70
-
GTP hydrolase and diphosphate phosphohydrolase activity Methanocaldococcus jannaschii

Turnover Number [1/s]

Turnover Number Minimum [1/s] Turnover Number Maximum [1/s] Substrate Comment Organism Structure
0.35
-
GTP pH 8.0, 70°C, GTP cyclohydrolase activity Methanocaldococcus jannaschii
0.5
-
GTP pH 8.0, 70°C, diphosphate phosphohydrolase activity Methanocaldococcus jannaschii

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
8 9 GTP hydrolase and diphosphate phosphohydrolase activity Methanocaldococcus jannaschii

Ki Value [mM]

Ki Value [mM] Ki Value maximum [mM] Inhibitor Comment Organism Structure
0.187
-
diphosphate
-
Methanocaldococcus jannaschii