Catechol oxidase
Overview
 
Catechol oxidase is an enzyme
Enzyme
Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...

 that catalyses
Catalysis
Catalysis is the change in rate of a chemical reaction due to the participation of a substance called a catalyst. Unlike other reagents that participate in the chemical reaction, a catalyst is not consumed by the reaction itself. A catalyst may participate in multiple chemical transformations....

 the oxidation of phenol
Phenol
Phenol, also known as carbolic acid, phenic acid, is an organic compound with the chemical formula C6H5OH. It is a white crystalline solid. The molecule consists of a phenyl , bonded to a hydroxyl group. It is produced on a large scale as a precursor to many materials and useful compounds...

s such as catechol. Catechol oxidase is a copper-containing enzyme whose activity is similar to that of tyrosinase
Tyrosinase
Tyrosinase also known as monophenol monooxygenase is an enzyme that catalyses the oxidation of phenols and is widespread in plants and animals...

, a related class of copper oxidase
Oxidase
An oxidase is any enzyme that catalyzes an oxidation-reduction reaction involving molecular oxygen as the electron acceptor. In these reactions, oxygen is reduced to water or hydrogen peroxide ....

s.

Catechol oxidase carries out the oxidation of phenols such as catechol, using dioxygen (O2). In the presence of catechol, benzoquinone is formed (see reaction below).
Encyclopedia
Catechol oxidase is an enzyme
Enzyme
Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...

 that catalyses
Catalysis
Catalysis is the change in rate of a chemical reaction due to the participation of a substance called a catalyst. Unlike other reagents that participate in the chemical reaction, a catalyst is not consumed by the reaction itself. A catalyst may participate in multiple chemical transformations....

 the oxidation of phenol
Phenol
Phenol, also known as carbolic acid, phenic acid, is an organic compound with the chemical formula C6H5OH. It is a white crystalline solid. The molecule consists of a phenyl , bonded to a hydroxyl group. It is produced on a large scale as a precursor to many materials and useful compounds...

s such as catechol. Catechol oxidase is a copper-containing enzyme whose activity is similar to that of tyrosinase
Tyrosinase
Tyrosinase also known as monophenol monooxygenase is an enzyme that catalyses the oxidation of phenols and is widespread in plants and animals...

, a related class of copper oxidase
Oxidase
An oxidase is any enzyme that catalyzes an oxidation-reduction reaction involving molecular oxygen as the electron acceptor. In these reactions, oxygen is reduced to water or hydrogen peroxide ....

s.

Catechol oxidase carries out the oxidation of phenols such as catechol, using dioxygen (O2). In the presence of catechol, benzoquinone is formed (see reaction below). Hydrogens removed from catechol combine with oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...

 to form water
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...

. This reaction, producing the brown
Brown
Brown is a color term, denoting a range of composite colors produced by a mixture of orange, red, rose, or yellow with black or gray. The term is from Old English brún, in origin for any dusky or dark shade of color....

 compound benzoquinone, is a form of enzymatic browning exhibited in many foods upon exposure to oxygen (e.g., in banana
Banana
Banana is the common name for herbaceous plants of the genus Musa and for the fruit they produce. Bananas come in a variety of sizes and colors when ripe, including yellow, purple, and red....

s).

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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