Properties of substituted 2-trifluoromethylbenzimidazoles as uncouplers of oxidative phosphorylation

For halogen- or mixed-halogen- and alkyl-substituted analogues, uncoupling activity was proportional to the acidity of the imidazole -NH group

OTG Jones; WA Watson

2015

Scholarcy highlights

  • For halogen- or mixed-halogen- and alkyl-substituted analogues, uncoupling activity was proportional to the acidity of the imidazole -NH group
  • Introduction of an -NH2 or -CO2H substituent caused a loss of uncoupling activity, as did alkylation at position 1 of the imidazole ring
  • Benzimidazoles active as uncouplers stimulated mitochondrial adenosine triphosphatase but not all stimulated the oxidation of succinate in the absence of a phosphate acceptor. 5. 4,5-Dichloro-2-trifluoromethylbenzimidazole inhibited the succinate-oxidase system at about the same concentration required for uncoupling and the site of this inhibition appears to lie between succinate dehydrogenase and cytochrome b
  • Concentrations of 4,5-dichloro-2-trifluoromethylbenzimidazole giving 50% uncoupling of oxidative phosphorylation were determined as described for Fig. 1
  • Dichloro analogue was very striking and did not appear to result from an inhibition of succinate dehydrogenase by accumulated oxaloacetate, since the effect was very rapid, not reversed by high concentrations of ATP, Amytal or added Ca2+

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