oxidoreductase activity, acting on paired donors, with oxidation of a pair of donors resulting in the reduction of molecular oxygen to two molecules of water

Definition

Target type: molecularfunction

Catalysis of an oxidation-reduction (redox) reaction in which hydrogen or electrons are transferred from each of two donors, and molecular oxygen is reduced to two molecules of water. [GOC:mah]

Oxidoreductase activity, acting on paired donors, with oxidation of a pair of donors resulting in the reduction of molecular oxygen to two molecules of water, encompasses a diverse group of enzymes that catalyze the transfer of electrons from two reducing equivalents (donors) to molecular oxygen. These enzymes are essential for various metabolic processes, including respiration, detoxification, and biosynthesis. The reaction mechanism involves the following steps:

1. **Binding of the two donors:** The enzyme binds two electron donors, each carrying a reducing equivalent, to its active site.
2. **Electron transfer:** The enzyme facilitates the transfer of electrons from the donors to the active site.
3. **Oxygen binding:** Molecular oxygen binds to the active site, typically through a metal ion cofactor, such as iron or copper.
4. **Reduction of oxygen:** The electrons from the donors are transferred to oxygen, reducing it to two molecules of water.

This process releases energy, which is often used to drive other cellular processes.

Key features of this activity include:

- **Paired donors:** The enzyme requires two donors to provide the necessary electrons for the reduction of oxygen.
- **Oxidation of donors:** The two donors are oxidized in the process, losing their electrons.
- **Reduction of oxygen:** Molecular oxygen is reduced to two molecules of water, gaining electrons.

Examples of enzymes with this activity include:

- **Cytochrome c oxidase:** This enzyme is a key component of the electron transport chain in mitochondria, where it catalyzes the transfer of electrons from cytochrome c to oxygen, producing water.
- **Monoamine oxidase:** This enzyme catalyzes the oxidation of neurotransmitters, such as dopamine and serotonin, using oxygen as an electron acceptor.
- **Flavoprotein oxidases:** These enzymes utilize flavin adenine dinucleotide (FAD) as a cofactor to catalyze the oxidation of various substrates, including fatty acids and alcohols, with oxygen as the electron acceptor.

The precise mechanism and substrate specificity vary among different oxidoreductases with this activity, but the fundamental principle of transferring electrons from two donors to oxygen remains constant.'
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Proteins (2)

Compounds (3)