Cytochrome Oxidase

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cytochrome oxidase

[′sīd·ə‚krōm ′äk·sə‚dās]
Any of a family of respiratory pigments that react directly with oxygen in the reduced state. Also known as cytochrome a3.

Cytochrome Oxidase


(also cytochrome a3), an enzyme of the oxido-reductase class; the final component of the chain of respiratory enzymes that carry electrons from the cytochrome c to molecular oxygen. Cytochrome oxidase was discovered in 1926 by the German scientist O. Warburg (Warburg’s respiratory enzyme). In plant and animal cells, it is localized on the inner membrane of mitochrondria. Chemically, it is a complex protein, whose molecule consists of two hemes, two copper atoms, and 20–30 percent lipid constituent. Both hemes are heme a; however, only part of the heme a is oxidized, and it is designated a3. It is still unclear whether cytochrome oxidase is a single protein with two functionally different forms of heme, or whether it is a complex of two different cytochromes. Copper is bound to the protein by a sulfur-containing ligand. When the copper is separated from the protein, cytochrome oxidase becomes inactive.

The molecular weight of cytochrome oxidase varies, according to different data, from 50,000 to 240,000. Cyanide, azide, CO, and hydroxylamine are cytochrome oxidase inhibitors.


References in periodicals archive ?
Reducing in the mtDNA copy number, mitochondrial cytochrome C oxidase activity and increase in ROS level could affect the subsequent embryo development.
STRING shows the interacting networks as evidence view of (A) T1 (preprotein translocase subunit SecD) and (B) T2 (ccoN:cbb3-type cytochrome c oxidase subunit I).
Decreased platelet cytochrome c oxidase activity is accompanied by increased blood lactate concentration during exercise in patients with Alzheimer disease," Experimental Neurology, vol.
Lalonde, "Regional brain metabolism with cytochrome c oxidase histochemistry in a PS1/A246E mouse model of autosomal dominant Alzheimer's disease: correlations with behavior and oxidative stress," Neurochemistry International, vol.
Cytochrome C oxidase (a) and citrate synthase (b) activity was measured spectrophotometrically (see Section 2).
The active response of callus to stress has been shown by the increasing amount of total phenolic compounds and higher activities of cytochrome c oxidase.
Cytochrome c oxidase dysfunction in oxidative stress.
There was a significant association of cytochrome c oxidase III 15bp deletion with human male infertility (p=0.
Cytochrome c oxidase (COX) transfers electrons from reduced cytochrome c to molecular oxygen.
Cytochrome c oxidase subunit I sequences###Eudrilus eugeniae###657###1-1M219171
Table 11,7: Nucleotide structure of 16S rDNA and Cytochrome c oxidase sequences in earthworms