Reaction participants Show >> << Hide
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Name help_outline
a ubiquinol
Identifier
CHEBI:17976
(CAS: 56275-39-9)
help_outline
Charge
0
Formula
C9H12O4(C5H8)n
Search links
Involved in 55 reaction(s)
Find proteins in UniProtKB for this molecule
Form(s) in this reaction:
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Identifier: RHEA-COMP:9566Polymer name: a ubiquinolPolymerization index help_outline nFormula C9H12O4(C5H8)nCharge (0)(0)nMol File for the polymer
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- Name help_outline O2 Identifier CHEBI:15379 (CAS: 7782-44-7) help_outline Charge 0 Formula O2 InChIKeyhelp_outline MYMOFIZGZYHOMD-UHFFFAOYSA-N SMILEShelp_outline O=O 2D coordinates Mol file for the small molecule Search links Involved in 2,648 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
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Name help_outline
a ubiquinone
Identifier
CHEBI:16389
(CAS: 1339-63-5)
help_outline
Charge
0
Formula
C9H10O4(C5H8)n
Search links
Involved in 49 reaction(s)
Find proteins in UniProtKB for this molecule
Form(s) in this reaction:
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Identifier: RHEA-COMP:9565Polymer name: a ubiquinonePolymerization index help_outline nFormula C9H10O4(C5H8)nCharge (0)(0)nMol File for the polymer
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- Name help_outline H2O Identifier CHEBI:15377 (Beilstein: 3587155; CAS: 7732-18-5) help_outline Charge 0 Formula H2O InChIKeyhelp_outline XLYOFNOQVPJJNP-UHFFFAOYSA-N SMILEShelp_outline [H]O[H] 2D coordinates Mol file for the small molecule Search links Involved in 6,048 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
RHEA:30255 | RHEA:30256 | RHEA:30257 | RHEA:30258 | |
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Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
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Related reactions help_outline
More general form(s) of this reaction
Publications
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A broad distribution of the alternative oxidase in microsporidian parasites.
Williams B.A., Elliot C., Burri L., Kido Y., Kita K., Moore A.L., Keeling P.J.
Microsporidia are a group of obligate intracellular parasitic eukaryotes that were considered to be amitochondriate until the recent discovery of highly reduced mitochondrial organelles called mitosomes. Analysis of the complete genome of Encephalitozoon cuniculi revealed a highly reduced set of p ... >> More
Microsporidia are a group of obligate intracellular parasitic eukaryotes that were considered to be amitochondriate until the recent discovery of highly reduced mitochondrial organelles called mitosomes. Analysis of the complete genome of Encephalitozoon cuniculi revealed a highly reduced set of proteins in the organelle, mostly related to the assembly of iron-sulphur clusters. Oxidative phosphorylation and the Krebs cycle proteins were absent, in keeping with the notion that the microsporidia and their mitosomes are anaerobic, as is the case for other mitosome bearing eukaryotes, such as Giardia. Here we provide evidence opening the possibility that mitosomes in a number of microsporidian lineages are not completely anaerobic. Specifically, we have identified and characterized a gene encoding the alternative oxidase (AOX), a typically mitochondrial terminal oxidase in eukaryotes, in the genomes of several distantly related microsporidian species, even though this gene is absent from the complete genome of E. cuniculi. In order to confirm that these genes encode functional proteins, AOX genes from both A. locustae and T. hominis were over-expressed in E. coli and AOX activity measured spectrophotometrically using ubiquinol-1 (UQ-1) as substrate. Both A. locustae and T. hominis AOX proteins reduced UQ-1 in a cyanide and antimycin-resistant manner that was sensitive to ascofuranone, a potent inhibitor of the trypanosomal AOX. The physiological role of AOX microsporidia may be to reoxidise reducing equivalents produced by glycolysis, in a manner comparable to that observed in trypanosomes. << Less
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Cyanide-insensitive Respiration in Plant Mitochondria.
Bendall D.S., Bonner W.D.
Pathways of electron transport have been studied in mitochondria isolated from hypocotyls of etiolated mung bean seedlings and skunk cabbage spadices that show cyanide-resistant respiratory activity. The residual flux through cytochrome c oxidase is shown to be small in comparison with the flux th ... >> More
Pathways of electron transport have been studied in mitochondria isolated from hypocotyls of etiolated mung bean seedlings and skunk cabbage spadices that show cyanide-resistant respiratory activity. The residual flux through cytochrome c oxidase is shown to be small in comparison with the flux through an unidentified alternative oxidase that is known to have a high affinity for oxygen. This alternative oxidase is not a cytochrome. Skunk cabbage and mung bean mitochondria contain cytochromes a and a(3) that have absorption peaks differing slightly from those of animal preparations. A slow oxidation-reduction of cytochrome a(3)-CN has been demonstrated. Cytochromes b undergo oxidation and reduction in the presence of cyanide but play no essential role in the cyanide-resistant pathway. Antimycin inhibits to an extent similar to that of cyanide; the respiratory chain bifurcates on the substrate side of the antimycin-sensitive site. Evidence is presented for the selective inhibition by thiocyanate, alpha, alpha'-dipyridyl, and 8-hydroxyquinoline of the alternative oxidase pathway, which may therefore contain a non-heme iron protein. << Less
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The active site of the cyanide-resistant oxidase from plant mitochondria contains a binuclear iron center.
Siedow J.N., Umbach A.L., Moore A.L.
The cyanide-resistant, alternative oxidase of plant mitochondria catalyzes the four-electron reduction of oxygen to water, but the nature of the catalytic center associated with this oxidase has yet to be elucidated. We have identified conserved amino acids, including two copies of the iron-bindin ... >> More
The cyanide-resistant, alternative oxidase of plant mitochondria catalyzes the four-electron reduction of oxygen to water, but the nature of the catalytic center associated with this oxidase has yet to be elucidated. We have identified conserved amino acids, including two copies of the iron-binding motif Glu-X-X-His, in the carboxy-terminal hydrophilic domain of the alternative oxidase that suggest the presence of a hydroxo-bridged binuclear iron center, analogous to that found in the enzyme methane monooxygenase. Using the known three-dimensional structures of other binuclear iron proteins, we have developed a structural model for the proposed catalytic site of the alternative oxidase based on these amino acid sequence similarities. << Less