Clearly SODs play a vital role in regulating a wide variety of signalling cascades and therefore need to exert a very constrained regulation to maintain homeostasis. Thus both the product and reactant of the reaction catalysed by the SOD family of enzymes are capable of causing oxidative damage and affecting signalling pathways.
At the same time, NO and superoxide react to produce peroxynitrate which is a highly reactive and dangerous free radical. On the other side of the SOD reaction, free radicals can also affect cell signalling by attenuating NO (nitric oxide) signalling and are necessary for long-term potentiation. Thus regulation of its turnover may not be as straightforward as simple detoxification. However, H 2O 2 also functions as a highly diffusible signalling molecule.
H 2O 2 is subsequently metabolized by catalase, peroxidases and other scavengers to oxygen and water thereby preventing damage from hydroxyl radicals.