Redox modulation

Redox modulation describes the changes in function that may occur in certain functional proteins, such as receptors, under physiological and pathological conditions, in response to changes in the balance of oxidants and antioxidants in the milieu of the protein, and to consecutive changes in its physico-chemical properties. These modulations are generally considered as integrated responses to the redox state of the surroundings, in that the changes in protein function trigger relevant responses to the given redox state.

Disulfides bonds between sulfur atoms of proteins are an essential "glue" contributing to give to this long string of amino acids its distinctive tridimensional shape. Oxidative stress may facilitate the stability of these bonds and, alternatively, some antioxidants can decrease the stability of these bonds (without denaturating irreversibly the protein).

Redox modulation may upregulate or downregulate functional proteins. For instance, a great number of proteins involved in the inflammatory cascade are upregulated by oxidative stress, while the main excitatory receptor in the brain, the NMDA receptor, is downregulated by oxidative stress (although ascorbate (vitamin C) and quinones appear to act paradoxically in this respect).

The emerging notion of redox modulation is necessary to understand the impact of oxidative stress and of antioxidants comprehensively.