Disease relevance of Ubiquinone Q2

• HMT2 protein, produced in and purified from Escherichia coli, was soluble, bound FAD, and catalyzed the reduction of quinone (coenzyme Q2) by sulfide [1].

High impact information on Ubiquinone Q2

• Ubiquinone-2 (Q2) and decylubiquinone showed high electron-accepting activity, and the steady-state kinetics and the NADH-Q2 oxidoreductase reaction were found to operate by a ping-pong reaction mechanism [2].
• In the reconstituted b-c1 complex, dicyclohexylcarbodiimide (DCCD) blocked the function of the electrogenic proton translocating device in the forward direction of proton ejection as well as in the backwards direction, measured as reversed electron flow from cytochrome b to coenzyme Q2 driven by a K+-diffusion potential [3].
• Oxidation of reduced coenzyme Q2 by the reconstituted vesicles with cytochrome c as oxidant showed the following energy-coupling phenomena [4].
• The redox states of exogenously added ubiquinone-2 and cytochrome c, and the protonmotive force (delta p) of rat liver mitochondria were measured as the respiration rate was titrated with the uncoupler carbonyl cyanide p-trifluoromethoxyphenyl-hydrazone [5].
• The affinities towards NADH and ubiquinone-2 were comparable to the ones obtained with the Escherichia coli complex I. The reaction was inhibited by piericidin A at the same concentration as in E. coli [6].

Biological context of Ubiquinone Q2

• The maximal rate obtained for the reduction of ubiquinone-2 by DQH2 via the Qout-binding domain, measured in the presence of antimycin, is similar to that catalysed by the Qin-binding domain of the non-inhibited enzyme and depends on the redox state of the high-potential electron carriers of the respiratory chain [7].
• Coenzyme Q2 induced p53-dependent apoptosis [8].

Anatomical context of Ubiquinone Q2

• Moreover, we considered the mitochondrial membrane potential producers to be divided into blocks of reactions that reduced or oxidized ubiquinone-2 (Q-2) and then measured the kinetic responses of these two blocks to changes in Q-2 redox state as well as the flux control coefficients and the cytochrome content [9].
• After reconstitution in phospholipid membranes, the preparation catalyses piericidin-A-sensitive electron transfer from NADH to ubiquinone-2 with Km values similar to those of complex I in cytoplasmic membranes but with only 10% of the Vmax value [10].
• Oxidizing activity for reduced coenzyme Q2 was also detected in the pressed vesicles but not in the spheroplasts [11].

Associations of Ubiquinone Q2 with other chemical compounds

• Short chain coenzyme Q homologues such as coenzyme Q2 give poor growth but compounds with saturated short aliphatic side chains from C10 to C18 produce good growth [12].
• The steady-state reduction of exogenous ubiquinone-2 by duroquinol as catalysed by the ubiquinol: cytochrome c oxidoreductase was studied in bovine heart mitoplasts [7].

Gene context of Ubiquinone Q2

• For example, coenzyme Q2 is known to decrease mitochondrial membrane potential whereas the analog with a 10C aliphatic side chain increases potential [12].

References