Mitochondrial electron transport stability

Cytochrome c occupies a prominent place in the mitochondrial electron-transport chain. Its water solubility, low molecular weight (12.4 kDa), stability, and ease of purification have allowed many experiments, which, when taken together, present a detailed picture of the structure and biological function of this... 

Q-cyde a cycle devised by P. Mitchell [FEBS Lett. 56 (1975) 1-6 S9 (1975) 137-139] to overcome the requirement of the redox loop mechanism (see Che-miosmotic hypothesis) for a H electron carrier in the cytochrome hq-containing Complex III of the mitochondrial electron transport chain, the Q.c. proposed that ubiquinone (coenzyme Q), the only mobile, hydrophobic redox component of the chain, participates in electron transfer from cytochrome b to cytochrome c, within Complex III by one-electron steps involving the fully reduced quinol-form (QH2), a stabilized free-radical semiquinone-form (QH ) and the fully oxidized quinone-form (Q). It also made use of the observation that cytochrome b appears to be a dimer composed of b- (b and b (b, which is buried deeply in the membrane with probably on the cytosolic side and by. on the matrix side. In the Hg., outlining the proposed mechanism, it can be seen that two protons are pumped across the membrane (steps 1 9 for uptake from the matrix and steps 3... 

Mitochondrial dynamics (fission, fusion, migration) has been reported to play an important role in neurotransmission, synaptic stability, and maintenance and neuronal survival. PBMKl and Parkin are closely associated within the regulation of mitochondrial dynamics and function (Bueler, 2009). Mutations in DJ-1, Parkin, and PINK 1 render animals more susceptible to oxidative stress and mitochondrial toxins implicated in sporadic PD. DJ-1, Parkin, and PINKl form a complex (termed PPD complex) to promote ubiquitination and degradation of Parkin substrates, including Parkin itself and synphilin-1. In addition, mutant proteins may retard the transport of nuclear-encoded mitochondrial proteins to mitochondria, interact with mitochondrial proteins and disrupt the electron transport chain, induce free radicals, cause... 

In spite of the absence of integral mitochondria, the red cell contains some of the enzymes (fumerase, isocitric dehydrogenase, malic dehydrogenase, and cytochrome oxidase) functioning in the Krebs cycle and electron transport. These enzymes probably represent mitochondrial remnants, and their presence in the mature erythrocyte may be a consequence of their greater stability. Similarly, enzymes concerned with... 

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