An oxygenase is any

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 ...

that oxidizes a

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 ...

by transferring the

oxygen Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), non ...

from molecular oxygen O₂ (as in air) to it. The oxygenases form a 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; their EC number is EC 1.13 or EC 1.14.

Structure

Most oxygenases contain either a metal, usually iron, or an organic cofactor, usually flavin. These cofactors interact with O₂, leading to its transfer to substrate. Oxygenases constitute a major intracellular source of

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 ...

and

carbon monoxide Carbon monoxide (chemical formula CO) is a poisonous, flammable gas that is colorless, odorless, tasteless, and slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the si ...

Mechanism

Two types of oxygenases are recognized: *

Monooxygenase Monooxygenases are enzymes that incorporate one hydroxyl group (−OH) into substrates in many metabolic pathways. In this reaction, the two atoms of dioxygen are reduced to one hydroxyl group and one H2O molecule by the concomitant oxidation of ...

s, or mixed function oxidase, transfer one oxygen atom to the substrate, and reduce the other oxygen atom to

water Water is an inorganic compound with the chemical formula . It is a transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance. It is the main constituent of Earth's hydrosphere and the fluids of all known liv ...

. *

Dioxygenase Dioxygenases are oxidoreductase enzymes. Aerobic organism, Aerobic life, from simple single-celled bacteria species to complex eukaryotic organisms, has evolved to depend on the oxidizing power of dioxygen in various metabolic pathways. From energ ...

s, or oxygen transferases, incorporate both atoms of molecular oxygen (O₂) into the product(s) of the reaction. Among the most common monooxygenases are the

cytochrome P450 oxidase Cytochromes P450 (P450s or CYPs) are a superfamily of enzymes containing heme as a cofactor that mostly, but not exclusively, function as monooxygenases. However, they are not omnipresent; for example, they have not been found in ''Escherich ...

s, responsible for breaking down numerous chemicals in the body.

History

Oxygenases were discovered in 1955 simultaneously by two groups, Osamu Hayaishi from Japan and Howard S. Mason from the US. Hayaishi was awarded the 1986 Wolf Prize in Medicine "for the discovery of the oxygenase enzymes and elucidation of their structure and biological importance."

References

Enzymes {{enzyme-stub