Ubiquinone (Coenzyme Q10) (CoQ10)

Ubiquinone, commonly referred to as Coenzyme Q10 (CoQ10), is a vital lipophilic molecule residing in the inner mitochondrial membrane where it constitutes the ubiquinone pool (PubChem CID 5281915). Its primary biological role is to serve as a mobile electron carrier in the mitochondrial electron transport chain, facilitating the transfer of electrons from Complexes I and II to Complex III to drive ATP synthesis (StatPearls: Coenzyme Q10). In addition to its bioenergetic function, the reduced form (ubiquinol) acts as a powerful antioxidant, protecting mitochondrial membranes and lipoproteins from oxidative damage (PMID: 25126052). Deficiencies in the ubiquinone pool, whether primary due to genetic mutations or secondary due to aging or drug use, are associated with mitochondrial myopathies, heart failure, and neurodegenerative disorders (PMID: 29108220). Therapeutically, CoQ10 and its synthetic analogs like idebenone are used to restore mitochondrial function and bypass respiratory chain defects (PMID: 28185602). Furthermore, certain drugs like atovaquone specifically target the ubiquinone binding site on Complex III to exert antimicrobial effects by disrupting pathogen respiration (DrugBank DB00303).

Other names

Coenzyme QUbidecarenoneMitochondrial ubiquinone poolCoQVitamin Q102,3-dimethoxy-5-methyl-6-decaprenyl-1,4-benzoquinone

The ubiquinone pool functions as a redox hub within the inner mitochondrial membrane, accepting electrons from NADH dehydrogenase (Complex I), succinate dehydrogenase (Complex II), and other flavoproteins, then transferring them to the cytochrome bc1 complex (Complex III) (StatPearls: Coenzyme Q10). This electron transfer is coupled to proton pumping, contributing to the electrochemical gradient used for ATP production. Drugs like atovaquone act as competitive inhibitors at the ubiquinone-binding (Qo) site of Complex III, effectively blocking the respiratory chain (PMID: 10411746).