Enzyme Commission Number
EC 1.14.18.1
Product Overview
High-quality enzyme products. Well-defined strains can be also provided for our clients to manufacture fermented products in a cost-effective way.
Features
Ready-to-use product, accelerating research progress, enhancing application performance.
Synonyms
monophenol monooxygenase; phenolase; monophenol oxidase; cresolase; monophenolase; tyrosine-dopa oxidase; monophenol monooxidase; monophenol dihydroxyphenylalanine:oxygen oxidoreductase; N-acetyl-6-hydroxytryptophan oxidase; monophenol, dihydroxy-L-phenylalanine oxygen oxidoreductase; o-diphenol:O2 oxidoreductase; phenol oxidase
Function
A type III copper protein 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 catalyse both a monophenolase reaction cycle (reaction 1) or a diphenolase reaction cycle (reaction 2). 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 catalysed by the related enzyme catechol oxidase (EC 1.10.3.1). However, the latter can not catalyse the hydroxylation or monooxygenation of monophenols.
Applications
Research Use
Molecular Weight
128 kDa by sedimentation velocity diffusion; 133 kDa by light-scattering measurements, and 119.5 kDa by electrophoresis.
Enzyme Class
Oxidoreductases
Production Methods
Fermentation
Activity
> 1000 unit/mg solid
Unit Definition
One unit = ΔA280 of 0.001 per min at pH 6.5 at 25°C in 3 mL reaction mix containing L-tyrosine.
Reaction
(1) L-tyrosine + O2 = dopaquinone + H2O (overall reaction)
(1a) L-tyrosine + ½ O2 = L-dopa
(1b) L-dopa + ½ O2 = dopaquinone + H2O
(2) 2 L-dopa + O2 = 2 dopaquinone + 2 H2O
Specification
On customer requests
