Cytochrome Oxidase

Also found in: Dictionary, Thesaurus, Medical, Wikipedia.
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.

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 ?
1) were used to obtain individual sequences of the mitochondrial (mtDNA) gene cytochrome oxidase c subunit 1 (CO1), and the nuclear (nDNA) genes 18S and 28S.
2003) is really shorthand for species identification by DNA sequencing, the chosen barcode region for animals being a 650 bp region of the mitochondrial cytochrome oxidase I gene (COI).
The brain is liable to be peroxidated by free radicals as a result of brain's high oxygen consumption rate, abundant lipid content and the related paucity of anti-oxidative enzymes (4, 22) Cyanide inhibits cytochrome oxidase of respiratory chain to block the effective ATP production and advances to impact mitochondrial function.
Each of these 16 had originally failed to meet only one of the criteria for verification: one isolate appeared to be cytochrome oxidase positive, 11 did not produce gas in EC broth, three were indole negative, and one appeared to be citrate positive.
We performed PCRs of the cestode-specific 12S rRNA gene (4) and cytochrome oxidase subunit 1 (cox1) (5).
The use of mitochondrial cytochrome oxidase mtCOI gene sequences for the identification of biotypes of Bemisia tabaci (Gennadius) in China.
603 bp) of the mitochondrial cytochrome oxidase III (CO3) gene from all Gambelia.
sikamea in both morphology and sequences of the mitochondrial 16S rRNA and cytochrome oxidase I gene fragments.
PACKAGE 15 - BELTS FOR DETECTION cytochrome oxidase
In 1938 Seeger discovered that cancer results from the inactivation or destruction of the most important enzyme of the respiratory chain, cytochrome oxidase, or more specifically, cytochrome a/a3.
All specimens were measured for the metrics reported in Brooks & Michener (1988) and the cytochrome oxidase I barcoding region was sequenced for a selection from each morphological cluster.