The enzyme catalyzes the hydroxylation of hypoxanthine to xanthine as well as xanthine to uric acid. It is an homodimeric enzyme and each subunit contains one molybdenum center, one flavin (FAD), and two [2Fe–2S] iron-sulfur centers (PMID15148401).
DETAILS ON METAL
MOS 3004 x |
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| The catalytic reaction takes place at the molybdenum center. The molybdenum is directly involved in the catalytic mechanism (substrate binding, redox center) (PMID15148401). |
| Site type | Physiological Metal |
| molybdopterin | molybdenum |
| Metal in the Resting State | |||
| Oxidation State |
Coordination Geometry | Coordination Number | PDB |
| 6 | squarePyramidal | 5 | - |
| Metal in the reaction stages | ||||||
| Step | Metal function(s) | Initial-Final Oxid. states | Initial-Final Geometry | Initial-Final Coord. # | Initial PDB | Final PDB |
| Step 1 | Coordinates substrate Electron pair acceptor Increases nucleophilicity |
+6 - +4 |
squarePyramidal - squarePyramidal |
5 - 5 | - | 1v97 |
| Step 2 | One electron donor Coordinates substrate |
+4 - +5 |
squarePyramidal - squarePyramidal |
5 - 5 | - | - |
| Step 3 | Coordinates substrate One electron donor |
+5 - +6 |
squarePyramidal - squarePyramidal |
5 - 5 | - | - |
| Step 4 | Not active |
+2 - +6 |
squarePyramidal - squarePyramidal |
5 - 5 | - | - |
* N.B. There may be steps that are not described in between two annotated steps. Consequently the product species of step n may differ from the reagent species of step n+1.