Is SDH complex 2?
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.
What type of enzyme is SDH?
Succinate dehydrogenase
Succinate dehydrogenase (SDH) also known as complex II or succinate:quinone oxidoreductase is an enzyme involved in both oxidative phosphorylation and tricarboxylic acid cycle; the processes that generate energy. SDH is a multi-subunit enzyme which requires a series of proteins for its proper assembly at several steps.
Is Complex II a proton pump?
Complex II does not pump protons directly. Complex II does send two protons on to Complex III in the form of the reduced ubiquinol.
Is SDH found in the cytosol?
Thus, succinate is not only a substrate for SDH in the mitochondria, but also a product of PHDs (and, one must add, of other a-ketoglutarate-dependent dioxygenases) in the cytosol.
Why is SDH important?
SDH-1 is the more important, functioning during aerobic growth to control the redox state of the menaquinone pool. It is a potential drug target; deletion of the Sdh1 operon increases levels of menaquinol, leading to increased oxygen consumption and maintenance of the stationary phase of the bacterium.
What is the substrate of complex II?
The mammalian mitochondrial electron transport chain (ETC) includes complexes I‑IV, as well as the electron transporters ubiquinone and cytochrome c. There are two electron transport pathways in the ETC: Complex I/III/IV, with NADH as the substrate and complex II/III/IV, with succinic acid as the substrate.
Is Complex 2 oxidized or reduced?
Complex II actually plays a part in another biochemical process, the citric acid cycle. One of the steps of the citric acid cycle is the oxidation of succinate to fumarate. It is during this oxidation that additional electrons are introduced into the electron transport chain via Complex II.
Where is SDH found in the cell?
inner mitochondrial membrane
SDH, a key enzyme of the respiratory chain, is located at the inner mitochondrial membrane and it is reported to be of critical functional importance when energy request is high [9,10].