Crystallization (Comment) | Organism |
---|---|
metal-bound [FeII/FeII]-ADEec and [FeII/MnII]-ADEec enzyme, sitting drop vapor diffusion, room temperature, X-ray diffraction struccture determination and analysis at 2.63-2.8 A resolution | Escherichia coli |
Protein Variants | Comment | Organism |
---|---|---|
D474N | site-directed mutagenesis, catalase inactive mutant | Escherichia coli |
H473N | site-directed mutagenesis, catalase inactive mutant | Escherichia coli |
General Stability | Organism |
---|---|
iron-bound [FeII/FeII]-ADE undergoes more than 100 turnovers with H2O2 before the enzyme is inactivated due to oxygenation of histidine residues critical for metal binding | Escherichia coli |
Inhibitors | Comment | Organism | Structure |
---|---|---|---|
6-Chloropurine | - |
Escherichia coli | |
H2O2 | excess H2O2 inhibits the enzyme. In the presence of excess H2O2, [FeII/FeII]-ADEec rapidly loses its ability to deaminate adenine | Escherichia coli | |
additional information | oxygenation of active site residues, inhibiting catalase activity, occurs via release of hydroxyl radicals | Escherichia coli |
Metals/Ions | Comment | Organism | Structure |
---|---|---|---|
Fe2+ | enzyme-bound, [FeII/FeII]-enzyme, required for activity. Disproportionation of H2O2 by the iron-bound enzyme involves the cycling of the binuclear metal center between the di-ferric and di-ferrous oxidation states | Escherichia coli | |
additional information | no acatalase acivit with Zn2+ or Mn2+-substituted enzyme | Escherichia coli |
Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
additional information | Escherichia coli | adenine deaminase, EC 3.5.4.2, from the amidohydrolase superfamily of enzymes catalyzes the conversion of adenine to hypoxanthine and ammonia. But it also catalyzes the catalase reaction converting H2O2 to H2O and O2. [MnII/MnII]-ADEec is active as a deaminase but not as a catalase. In contrast, [FeII/FeII]-ADEec catalyzes both reactions | ? | - |
? |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Escherichia coli | - |
- |
- |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
2 H2O2 | - |
Escherichia coli | O2 + 2 H2O | - |
? | |
additional information | adenine deaminase, EC 3.5.4.2, from the amidohydrolase superfamily of enzymes catalyzes the conversion of adenine to hypoxanthine and ammonia. But it also catalyzes the catalase reaction converting H2O2 to H2O and O2. [MnII/MnII]-ADEec is active as a deaminase but not as a catalase. In contrast, [FeII/FeII]-ADEec catalyzes both reactions | Escherichia coli | ? | - |
? |
Turnover Number Minimum [1/s] | Turnover Number Maximum [1/s] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
200 | - |
H2O2 | pH 7.5, 30°C | Escherichia coli |
General Information | Comment | Organism |
---|---|---|
additional information | reaction mechanism of catalase activity, overview. The iron in the active site is in an uncoupled high-spin ferric oxidation state. The metal ions can be reduced back to the di-ferrous state with dithionite but the deaminase activity is not recovered. Therefore, addition of an excess of H2O2 to [FeII/FeII]-ADEec irreversibly modifies the protein and stabilizes the [FeIII/FeIII] state | Escherichia coli |
kcat/KM Value [1/mMs-1] | kcat/KM Value Maximum [1/mMs-1] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
24 | - |
H2O2 | pH 7.5, 30°C | Escherichia coli |