Cytochrome Oxidase

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Related to Cytochrome Oxidase: Cytochrome P450

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 It might be outdated or ideologically biased.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 ?
DNA extracts were used to amplify the DNA fragment barcode (barcode) of ~700 nt of mitochondrial gene cytochrome oxidase I with the MTNF / MTNR (Hebert et al.
2007), although cytochrome oxidase c subunit I (CO1) is used frequently to distinguish differences between close species.
Table 1--Collection localities, GenBank accession numbers for the cytochrome oxidase subunit 1 sequences, and catalog numbers for voucher specimens of Ictalurus from northwestern Mexico.
The diffuse pattern of Na/K pump activity in the +/Lc cerebellar cortex is in stark contrast to the distribution of cytochrome oxidase (COX) histochemical staining at the same ages [26].
These signaling events may include the activation of immediate early genes, transcription factors, cytochrome oxidase subunit gene expression, and a host of other enzymes and pathways related to increased oxidative metabolism [13, 14].
The cytochrome oxidase II (COII) a mitochondrial gene is available in multiple copies per cell which increases the chances of good amplification from the extract of predator's gut (Zhang et al., 2007).
Levy et al studied the role of exogenous cytochrome C on myocardial function in an animal model of sepsis 24 hours after CLP and found that exogenous cytochrome C restored myocardial cytochrome oxidase activity and improved cardiac function.
One mitochondrial gene, cytochrome oxidase I (COI), is frequently used in studies of species classification, identification and phylogenetic relationships (Caterino et al., 2000; Cai et al., 2005; Ma, 2010).
The samples contained specimens of Frankenbergerius forcipatus (Harold, 1881), and tissue from some of these specimens was used to obtain nucleotide sequences of the mitochondrial cytochrome oxidase I (COI) gene.