Mitochondrial nitric oxide synthase (mtNOS), a voltage-dependent enzyme, is responsible for NO diffusion to cytosol

VALDEZ LB; BOVERIS A

Proceedings of the XIII Biennial Meeting of the Society for Free Radical Research

Monduzzi Editore SpA - Medimond Inc

Lugar: Bologna, Italy; Año: 2006; p. 35 - 40

The mitochondrial metabolic state regulates the rate of mitochondrial NO production and release to the cytosol: NO release is 45% lower in state 3 than in state 4. The activity of mtNOS is driven by the membrane potential and not by intramitochondrial pH changes. The release of NO by mitochondria showed an exponential dependence on membrane potential, supporting the speculation that not only H2O2 but also NO are biological signals that report a high mitochondrial energy charge to the cytosol. The marked regulation of mtNOS activity, as a voltage-dependent enzyme and at the physiological range of membrane potentials, makes mtNOS a highly sensitive enzyme that in turn regulates mitochondrial O2 uptake and H2O2 production.