ENZYME entry: EC 1.14.18.1
| Accepted Name |
|---|
| Tyrosinase.
|
| Alternative Name(s) |
|---|
| Cresolase. |
| Monophenol monooxygenase. |
| Monophenol oxidase. |
| N-acetyl-6-hydroxytryptophan oxidase. |
| Phenolase. |
| Tyrosine-dopa oxidase. |
| Reaction catalysed |
|---|
- 2 L-dopa + O(2) <=> 2 dopaquinone + 2 H(2)O
- L-tyrosine + O(2) <=> dopaquinone + H(2)O
|
| Cofactor(s) |
|---|
| Copper.
|
| Comment(s) |
|---|
- Found in a broad variety of bacteria, fungi, plants, insects,
crustaceans, and mammals, which is involved in the synthesis of
betalains and melanin.
- The enzyme, which is activated upon binding molecular oxygen,
can catalyze both a monophenolase reaction cycle or a diphenolase
reaction cycle.
- During the monophenolase cycle, one of the bound oxygen atoms is
transferred to a monophenol (such as L-tyrosine), generating an
O-diphenol intermediate, which is subsequently oxidized to an
o-quinone and released, along with a water molecule.
- The enzyme remains in an inactive deoxy state, and is restored to the
active oxy state by the binding of a new oxygen molecule.
- During the diphenolase cycle the enzyme binds an external diphenol
molecule (such as L-dopa) and oxidizes it to an O-quinone that is
released along with a water molecule, leaving the enzyme in the
intermediate met state.
- The enzyme then binds a second diphenol molecule and repeats the
process, ending in a deoxy state.
- The second reaction is identical to that catalyzed by the related
enzyme catechol oxidase (EC 1.10.3.1).
- However, the latter can not catalyze the hydroxylation or
monooxygenation of monophenols.
- Formerly EC 1.14.17.2.
|
| Cross-references |
|---|
| PROSITE | PDOC00398 |
| BRENDA | 1.14.18.1 |
| EC2PDB | 1.14.18.1 |
| ExplorEnz | 1.14.18.1 |
| PRIAM enzyme-specific profiles | 1.14.18.1 |
| KEGG Ligand Database for Enzyme Nomenclature | 1.14.18.1 |
| IUBMB Enzyme Nomenclature | 1.14.18.1 |
| IntEnz | 1.14.18.1 |
| MEDLINE | Find literature relating to 1.14.18.1 |
| MetaCyc | 1.14.18.1 |
| UniProtKB/Swiss-Prot |
| Q00024, PPO1_AGABI; | O42713, PPO2_AGABI; | C7FF04, PPO3_AGABI; |
| C7FF05, PPO4_AGABI; | Q27451, PRP1_BOMMO; | O44249, PRP1_MANSE; |
| P85046, PRP1_SIMDA; | Q27452, PRP2_BOMMO; | Q25519, PRP2_MANSE; |
| Q9V521, PRPA3_DROME; | Q8I1F6, PRPD3_DROER; | Q9W1V6, PRPD3_DROME; |
| Q8J130, TYRO_ASPFU; | Q00234, TYRO_ASPOR; | Q8MIU0, TYRO_BOVIN; |
| P54834, TYRO_CANFA; | P55024, TYRO_CHICK; | Q08410, TYRO_COTJA; |
| P55033, TYRO_FELCA; | Q9BDE0, TYRO_GORGO; | P14679, TYRO_HUMAN; |
| P11344, TYRO_MOUSE; | P00440, TYRO_NEUCR; | P55025, TYRO_ORYLA; |
| Q04604, TYRO_PELNI; | P55026, TYRO_PELSI; | A7BHQ9, TYRO_PHONA; |
| Q92396, TYRO_PODAS; | P33180, TYRO_RHIML; | P07524, TYRO_STRAT; |
| P06845, TYRO_STRGA; | P55022, TYRO_STRGB; | P55023, TYRO_STRLN; |
|
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