CATH Classification

Domain Context

CATH Clusters

Superfamily Hemocyanin, C-terminal domain
Functional Family Hemocyanin subunit 2

Enzyme Information

1.14.18.1
Tyrosinase.
based on mapping to UniProt O44249
(1) L-tyrosine + O(2) = dopaquinone + H(2)O. (2) 2 L-dopa + O(2) = 2 dopaquinone + 2 H(2)O.
-!- 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.

UniProtKB Entries (1)

Q25519
PRP2_MANSE
Manduca sexta
Phenoloxidase subunit 2

PDB Structure

PDB 3HHS
External Links
Method X-RAY DIFFRACTION
Organism
Primary Citation
Crystal structure of Manduca sexta prophenoloxidase provides insights into the mechanism of type 3 copper enzymes.
Li, Y., Wang, Y., Jiang, H., Deng, J.
Proc.Natl.Acad.Sci.USA