Catechol dioxygenases are

metalloprotein Metalloprotein is a generic term for a protein that contains a metal ion cofactor. A large proportion of all proteins are part of this category. For instance, at least 1000 human proteins (out of ~20,000) contain zinc-binding protein domains al ...

enzyme An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different mol ...

s that carry out the oxidative cleavage of

catechol Catechol ( or ), also known as pyrocatechol or 1,2-dihydroxybenzene, is an organic compound with the molecular formula . It is the ''ortho'' isomer of the three isomeric benzenediols. This colorless compound occurs naturally in trace amounts. It ...

s. This class of enzymes incorporate

dioxygen There are several known allotropes of oxygen. The most familiar is molecular oxygen (), present at significant levels in Earth's atmosphere and also known as dioxygen or triplet oxygen. Another is the highly reactive ozone (). Others are: * Ato ...

into the

substrate Substrate may refer to: Physical layers *Substrate (biology), the natural environment in which an organism lives, or the surface or medium on which an organism grows or is attached ** Substrate (aquatic environment), the earthy material that exi ...

. Catechol dioxygenases belong to the class of

oxidoreductase In biochemistry, an oxidoreductase is an enzyme that catalyzes the transfer of electrons from one molecule, the reductant, also called the electron donor, to another, the oxidant, also called the electron acceptor. This group of enzymes usually ut ...

s and have several different substrate specificities, including

catechol 1,2-dioxygenase Catechol 1,2- dioxygenase (, ''1,2-CTD'', ''catechol-oxygen 1,2-oxidoreductase'', ''1,2-pyrocatechase'', ''catechase'', ''catechol 1,2-oxygenase'', ''catechol dioxygenase'', ''pyrocatechase'', ''pyrocatechol 1,2-dioxygenase'', ''CD I'', ''CD II'' ...

(), catechol 2,3-dioxygenase (), and protocatechuate 3,4-dioxygenase (). The active site of catechol dioxygenases most frequently contains

iron Iron is a chemical element; it has symbol Fe () and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, forming much of Earth's o ...

, but

manganese Manganese is a chemical element; it has Symbol (chemistry), symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese was first isolated in the 1770s. It is a transition m ...

-containing forms are also known. The ''

Pseudomonas putida ''Pseudomonas putida'' is a Gram-negative, rod-shaped, saprophytic soil bacterium. It has a versatile metabolism and is amenable to genetic manipulation, making it a common organism used in research, bioremediation, and synthesis of chemicals and ...

'' xylE gene, which encodes catechol 2,3-dioxygenase, is often used as a reporter to quantitate gene expression. An example of the reaction carried out by catechol 1,2-dioxygenase is the formation of ''cis,cis''-muconic acid from

, shown below.

References

* Stephen J. Lippard, Jeremy M. Berg, ''Principles of Bioinorganic Chemistry'', University Science Books, 1994, * J.J.R. Fraústo da Silva and R.J.P. Williams, ''The biological chemistry of the elements: The inorganic chemistry of life'', 2nd Edition, Oxford University Press, 2001, {{Portal bar, Biology, border=no EC 1.13.11 Natural phenols metabolism

See also

References