Uncoupling effect of a low homolog of unbiquinone (UQ-3) in rabbit heart mitochondria.

Short-chain ubiquinone (UQ-3) inhibits ADP-stimulated respiration (state 3) in intact rabbit heart mitochondria. This effect appears to be similar in all the three sites of oxidative phosphorylation by using different respiratory substrates. Ubiquinone-3 also immobilizes lipids into mitochondrial membranes indicating that the uncoupling effect might be a consequence of an altered physical state of membrane lipids.