Activating Compound | Comment | Organism | Structure |
---|---|---|---|
NH4+ | activation of GTP cyclohydrolase activity, maximal activity at 50 mM | Methanocaldococcus jannaschii |
Cloned (Comment) | Organism |
---|---|
expression in Escherichia coli | Methanocaldococcus jannaschii |
Protein Variants | Comment | Organism |
---|---|---|
H136Q | approx. 7 and 15% of wild-type GTP cyclohydrolase and diphosphate phosphohydrolase activity, respectively | Methanocaldococcus jannaschii |
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 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 | 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 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 | UniProt | Comment | Textmining |
---|---|---|---|
Methanocaldococcus jannaschii | Q57609 | hyperthermophilic euryarcheon | - |
Purification (Comment) | Organism |
---|---|
heating, streptomycin, Mono Q, Sephacryl, recombinant enzyme | Methanocaldococcus jannaschii |
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 Minimum [µmol/min/mg] | Specific Activity Maximum [µmol/min/mg] | Comment | Organism |
---|---|---|---|
0.39 | - |
recombinant enzyme | Methanocaldococcus jannaschii |
Storage Stability | Organism |
---|---|
4°C, 50 mM TAPS/KOH, pH 8.0, 150 mM KCl, 9 weeks, 20% loss of activity | Methanocaldococcus jannaschii |
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 | 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 Maximum [°C] | Comment | Organism |
---|---|---|---|
70 | - |
GTP hydrolase and diphosphate phosphohydrolase activity | Methanocaldococcus jannaschii |
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 Minimum | pH Optimum Maximum | Comment | Organism |
---|---|---|---|
8 | 9 | GTP hydrolase and diphosphate phosphohydrolase activity | Methanocaldococcus jannaschii |
Ki Value [mM] | Ki Value maximum [mM] | Inhibitor | Comment | Organism | Structure |
---|---|---|---|---|---|
0.187 | - |
diphosphate | - |
Methanocaldococcus jannaschii |