Electron Transport & Oxidative Phosphorylation: Difference between revisions
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'''Succinate-Q oxidoreductase (complex II)''' | '''Succinate-Q oxidoreductase (complex II)''' | ||
*[[Succinate Dehydrogenase]] | *[[Succinate Dehydrogenase]] | ||
Succinate-Q oxidoreductase, also known as complex II or succinate dehydrogenase, is a second entry point to the electron transport chain. It is unusual because it is the only enzyme that is part of both the citric acid cycle and the electron transport chain. Complex II consists of four protein subunits and contains a bound flavin adenine dinucleotide (FAD) cofactor, iron–sulfur clusters, and a heme group that does not participate in electron transfer to coenzyme Q, but is believed to be important in decreasing production of reactive oxygen species. | Succinate-Q oxidoreductase, also known as complex II or succinate dehydrogenase, is a second entry point to the electron transport chain. It is unusual because it is the only enzyme that is part of both the citric acid cycle and the electron transport chain. Complex II consists of four protein subunits and contains a bound <scene name='43/430899/Cv/4'>flavin adenine dinucleotide</scene> (FAD) cofactor, iron–sulfur clusters, and a heme group that does not participate in electron transfer to coenzyme Q, but is believed to be important in decreasing production of reactive oxygen species. | ||
<scene name='43/430893/Cv/10'>Succinate</scene> + Q -> <scene name='43/430893/Cv/11'>Fumarate</scene> + QH2 | <scene name='43/430893/Cv/10'>Succinate</scene> + Q -> <scene name='43/430893/Cv/11'>Fumarate</scene> + QH2 | ||
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'''Q-cytochrome c oxidoreductase (complex III)''' | '''Q-cytochrome c oxidoreductase (complex III)''' | ||
* [[Complex III of Electron Transport Chain]] | * [[Complex III of Electron Transport Chain]] | ||
* [[Cytochrome bc1 complex]] | |||
* [[Cytochrome b]] | |||
The reaction catalyzed by complex III is the oxidation of one molecule of ubiquinol and the reduction of two molecules of cytochrome c, a heme protein loosely associated with the mitochondrion. Unlike coenzyme Q, which carries two electrons, cytochrome c carries only one electron. | |||
QH<sub>2</sub>+ 2 Cyt c<sub>ox</sub> + 2H<sup>+</sup>(matrix) -> Q + 2 Cyt c<sub>red</sub> + 4H<sup>+</sup>(intermembrane) | |||
'''Cytochrome c oxidase (complex IV)''' | |||
*[[Cytochrome c oxidase]] | |||
Cytochrome c oxidase, also known as complex IV, is the final protein complex in the electron transport chain. The mammalian enzyme has an extremely complicated structure and contains <scene name='46/466466/Cv/9'>13 subunits</scene>, two <scene name='46/466466/Cv/10'>heme groups, as well as multiple metal ion cofactors – in all, three atoms of copper, one of magnesium and one of zinc</scene>. The fully oxidized form of <scene name='46/466466/Cv/11'>CcO active site shows the heme, Cu+2 ion and an O2</scene> molecule. <scene name='46/466466/Cv/12'>Second heme binding site</scene>. <ref>PMID:9624044</ref> Bacterial CcO is composed of 2 subunits. | |||
4Cyt c<sub>red</sub> +O<sub>2</sub> + 8H<sup>+</sup>(matrix) -> 4Cyt c<sub>ox</sub> + 2H<sub>2</sub>O +4H<sup>+</sup>(intermembrane) | |||
</StructureSection> | </StructureSection> | ||
== References == | |||
<references/> | |||