Energy metabolism ubiquinone

In summary, methanophenazine (10) is the first phenazine whose involvement in the electron transport of biologic systems could be established. The experiments indicate that its role in the energy metabolism of methanogens corresponds to that of ubiquinones in mitochondria and bacteria. 

Focusing on the mechanisms of action of BOA into the plant cell, Barnes et al.7 suggested that the chlorotic seedlings observed in the presence of BOA and DIBOA could be the consequence of a benzoxazinone effect on the photophosphorylation and electron transport into the plant metabolism. In this way, Niemeyer et al.28 studied the effects of BOA on energy-linked reactions in mitochondria and reported an inhibition of the electron transfer between flavin and ubiquinone in Complex I, with complete inhibition of electron transport from NADH to oxygen in SMP. They could also detect an inhibition of BOA on ATP synthesis by acting directly on the ATPase complex at the F1 moiety. 

Figure 37.2 Cartoon depicting enzymes participating in mitochondrial P-oxidation and part of the respiratory chain. Acyl-CoA substrates derived from fatty acid and amino acid metabolism are oxidized by several flavin-containing acyl-CoA dehydrogenases (ACAD). Electrons obtained from this reaction are shuttled to the respiratory chain via the ETF/ETF QO hub (electron-transfer flavoprotein and electron-transfer flavoprotein ubiquinone oxidoreductase). ETF QO is able to transfer electrons to ubiquinone (Q) (such as respiratory complexes I and II) whose subsequent transfer down to complex IV will result in energy conservation and ATP production. See list of abbreviations for definitions.

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