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 |
|