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.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

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.


The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
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.
Stuart, "The cytochrome bc1 and cytochrome c oxidase complexes associate to form a single supracomplex in yeast mitochondria," The Journal of Biological Chemistry, vol.
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).
The activity of cytochrome c oxidase, an important enzyme in mitochondrial ETC, increased when higher amount of copper is applied.
We found that low-intensity 670 nm LED irradiation for 3 days improved cell viability, cytochrome C oxidase activity, and ATP content of hypoxic RF/6A cells damaged by Co[Cl.sub.2] exposure.
Oliveira, "Cytochrome c oxidase is decreased in Alzheimer's disease platelets," Neurobiology of Aging, vol.
Finally, the expression of cytochrome C oxidase chain I, an important mitochondrial proton-pumping respiratory protein, and NADH dehydrogenase subunit 4, involved in glycolosis and cellular respiration, appeared to be unchanged across all treatments.
In the present study we identified the hyperparasitoid from the cotton mealybug and sequenced two marker genes, the mitochondrial cytochrome c oxidase I (COI) and the ribosomal internal transcribed spacer 1 (ITS1), and developed and applied PCR primers for hyperparasitism detection in mealybug host using PCR.
The mitochondrial genome contains genes encoding many ribosomal RNAs and three components of cellular respiration (cytochrome c oxidase gene I, cytochrome c oxidase gene III and cytochrome b).
By using 3 DNA sequences commonly used in the molecular systematics of filarial parasites (the nuclear internal transcribed spacer 1 [ITS1]-based ribosomal DNA sequence [7] and the mitochondrial 12S and cytochrome c oxidase subunit 1 genes [6]), we confirmed M.
CYP2E1 generates large amounts of ROS that can damage cellular and mitochondrial components, such as mitochondrial DNA and cytochrome c oxidase, enhancing local and cellular oxidative stress [72].