Guanosine diphosphate exerts a lower effect on superoxide release from mitochondrial matrix in the brains of uncoupling protein-2 knockout mice: New evidence for a putative novel function of uncoupling proteins as superoxide anion transporters.

In this report, we show new experimental evidence that, in mouse brain mitochondria, uncoupling protein-2 (UCP2) can be involved in superoxide (O2-) removal from the mitochondrial matrix. We found that the effect of guanosine 5'-diphosphate (GDP) on the rate of reactive oxygen species (ROS) release from brain mitochondria of UCP2 knockout mice was less pronounced compared to the wild type animals. This putative novel UCP2 activity, evaluated by the use of UCP2-knockout transgenic animals, along with the known antioxidant defence systems, may provide additional protection from ROS in brain mitochondria.