| Accepted Name |
|---|
| tyrosinase
|
| Alternative Name(s) |
|---|
| cresolase |
| monophenol monooxygenase |
| monophenol oxidase |
| N-acetyl-6-hydroxytryptophan oxidase |
| phenolase |
| tyrosine-dopa oxidase |
| Reaction catalysed |
|---|
- L-tyrosine + O2 <=> H2O + L-dopaquinone
- 2 L-dopa + O2 <=> 2 H2O + 2 L-dopaquinone
|
| 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 |
|---|
| 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 |
| Rhea expert-curated reactions | 1.14.18.1 |
| UniProtKB/Swiss-Prot |
| Q00024, PPO1_AGABI | Q3ZPT5, PPO1_SPOLT | O42713, PPO2_AGABI |
| Q9V521, PPO2_DROME | C7FF04, PPO3_AGABI | Q8I1F6, PPO3_DROER |
| Q9W1V6, PPO3_DROME | C0HJM0, PPO3_SARAR | C7FF05, PPO4_AGABI |
| Q27451, PRP1_BOMMO | O44249, PRP1_MANSE | P85046, PRP1_SIMDA |
| Q27452, PRP2_BOMMO | Q6UEH6, PRP2_GALME | Q25519, PRP2_MANSE |
| Q8J130, TYRO_ASPFU | Q00234, TYRO_ASPOR | Q8MIU0, TYRO_BOVIN |
| P54834, TYRO_CANLF | P55024, TYRO_CHICK | Q08410, TYRO_COTJA |
| P55033, TYRO_FELCA | Q9BDE0, TYRO_GORGO | P14679, TYRO_HUMAN |
| P11344, TYRO_MOUSE | P00440, TYRO_NEUCR | P55025, TYRO_ORYLA |
| Q0MVP0, TYRO_PELLE | 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 | B8NM74, USTQ_ASPFN |
|
