ID 1.14.18.1 DE tyrosinase. AN cresolase. AN monophenol monooxygenase. AN monophenol oxidase. AN N-acetyl-6-hydroxytryptophan oxidase. AN phenolase. AN tyrosine-dopa oxidase. CA (1) L-tyrosine + O2 = H2O + L-dopaquinone. CA (2) 2 L-dopa + O2 = 2 H2O + 2 L-dopaquinone. CC -!- Found in a broad variety of bacteria, fungi, plants, insects, CC crustaceans, and mammals, which is involved in the synthesis of CC betalains and melanin. CC -!- The enzyme, which is activated upon binding molecular oxygen, CC can catalyze both a monophenolase reaction cycle or a diphenolase CC reaction cycle. CC -!- During the monophenolase cycle, one of the bound oxygen atoms is CC transferred to a monophenol (such as L-tyrosine), generating an CC O-diphenol intermediate, which is subsequently oxidized to an CC o-quinone and released, along with a water molecule. CC -!- The enzyme remains in an inactive deoxy state, and is restored to the CC active oxy state by the binding of a new oxygen molecule. CC -!- During the diphenolase cycle the enzyme binds an external diphenol CC molecule (such as L-dopa) and oxidizes it to an O-quinone that is CC released along with a water molecule, leaving the enzyme in the CC intermediate met state. CC -!- The enzyme then binds a second diphenol molecule and repeats the CC process, ending in a deoxy state. CC -!- The second reaction is identical to that catalyzed by the related CC enzyme catechol oxidase (EC 1.10.3.1). CC -!- However, the latter can not catalyze the hydroxylation or CC monooxygenation of monophenols. CC -!- Formerly EC 1.14.17.2. DR Q00024, PPO1_AGABI ; Q3ZPT5, PPO1_SPOLT ; O42713, PPO2_AGABI ; DR Q9V521, PPO2_DROME ; C7FF04, PPO3_AGABI ; Q8I1F6, PPO3_DROER ; DR Q9W1V6, PPO3_DROME ; C0HJM0, PPO3_SARAR ; C7FF05, PPO4_AGABI ; DR Q27451, PRP1_BOMMO ; O44249, PRP1_MANSE ; P85046, PRP1_SIMDA ; DR Q27452, PRP2_BOMMO ; Q6UEH6, PRP2_GALME ; Q25519, PRP2_MANSE ; DR Q8J130, TYRO_ASPFU ; Q00234, TYRO_ASPOR ; Q8MIU0, TYRO_BOVIN ; DR P54834, TYRO_CANLF ; P55024, TYRO_CHICK ; Q08410, TYRO_COTJA ; DR P55033, TYRO_FELCA ; Q9BDE0, TYRO_GORGO ; P14679, TYRO_HUMAN ; DR P11344, TYRO_MOUSE ; P00440, TYRO_NEUCR ; P55025, TYRO_ORYLA ; DR Q0MVP0, TYRO_PELLE ; Q04604, TYRO_PELNI ; P55026, TYRO_PELSI ; DR A7BHQ9, TYRO_PHONA ; Q92396, TYRO_PODAS ; P33180, TYRO_RHIML ; DR P07524, TYRO_STRAT ; P06845, TYRO_STRGA ; P55022, TYRO_STRGB ; DR P55023, TYRO_STRLN ; B8NM74, USTQ_ASPFN ; //