Mitochondrial respiratory chain and dehydrogenases (MRC)

The mitochondrial respiratory chain and associated dehydrogenases constitute the core machinery for cellular energy production and metabolic regulation within the mitochondria [17, 18]. This system includes the four primary complexes of the electron transport chain (Complexes I-IV) and various dehydrogenases, such as succinate dehydrogenase (Complex II), pyruvate dehydrogenase, and dihydroorotate dehydrogenase, which feed electrons into the respiratory chain [10, 14, 16]. Their collective biological function is to drive oxidative phosphorylation, producing ATP while maintaining cellular redox balance and regulating signaling pathways like apoptosis and reactive oxygen species (ROS) production [1, 8, 17]. Dysfunctions in these enzymes are implicated in a wide range of pathologies, including primary mitochondrial diseases (e.g., Leigh syndrome), neurodegenerative disorders, type 2 diabetes, and cancer, where they support the high metabolic demands of tumor cells [3, 6, 18, 19]. Therapeutic interventions target these enzymes for diverse purposes: metformin inhibits Complex I to manage blood glucose, atovaquone targets Complex III for antimalarial activity, and DHODH inhibitors are explored for oncology and autoimmune diseases [6, 12, 15, 16]. However, because these pathways are fundamental to life, pharmacological modulation requires careful management to avoid severe side effects like lactic acidosis or organ-specific toxicity [1, 12]. Overall, the mitochondrial respiratory chain represents a complex but vital therapeutic landscape for addressing both metabolic and degenerative conditions [9, 18].

Other names

Electron transport chainOxidative phosphorylation systemmETCMitochondrial electron transport chainMitochondrial oxidoreductases

Inhibition of electron transfer within the respiratory complexes, uncoupling of oxidative phosphorylation from ATP synthesis, modulation of reactive oxygen species production, and restoration of mitochondrial bioenergetics through cofactor supplementation or alternative electron carriers.