Figure 2: “Antioxidative activity” of UCP. High transmembrane proton gradient and membrane potential of mitochondria will induce ROS production and thus oxidative damage; these ROSs may activate UCPs and therefore cause a “mild uncoupling” and (as a negative feedback) will prevent further superoxide production and decrease oxidative damage. ΔpH: transmembrane proton gradient; : mitochondrial membrane potential.