succinate dehydrogenase (succinate-ubiquinone oxidoreductase) | |||||||||
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![]() The structure of SQR in a phospholipid membrane. SdhA, SdhB, SdhC and SdhD | |||||||||
Identifiers | |||||||||
EC no. | 1.3.5.1 | ||||||||
CAS no. | 9028-11-9 | ||||||||
Databases | |||||||||
IntEnz | IntEnz view | ||||||||
BRENDA | BRENDA entry | ||||||||
ExPASy | NiceZyme view | ||||||||
KEGG | KEGG entry | ||||||||
MetaCyc | metabolic pathway | ||||||||
PRIAM | profile | ||||||||
PDB structures | RCSB PDB PDBe PDBsum | ||||||||
Gene Ontology | AmiGO / QuickGO | ||||||||
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Succinate dehydrogenase | |
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Identifiers | |
Symbol | Respiratory complex II |
OPM superfamily | 3 |
OPM protein | 1zoy |
Membranome | 656 |
Succinate dehydrogenase (SDH) or succinate-coenzyme Q reductase (SQR) or respiratory complex II is an enzyme complex, found in many bacterial cells and in the inner mitochondrial membrane of eukaryotes. It is the only enzyme that participates in both the citric acid cycle and the electron transport chain.[1] Histochemical analysis showing high succinate dehydrogenase in muscle demonstrates high mitochondrial content and high oxidative potential.[2]
In step 6 of the citric acid cycle, SQR catalyzes the oxidation of succinate to fumarate with the reduction of ubiquinone to ubiquinol. This occurs in the inner mitochondrial membrane by coupling the two reactions together.