SUPEROXIDE, HYDROGEN-PEROXIDE AND NITRIC-OXIDE AS SIGNALING MOLECULES- THEIR PRODUCTION AND ROLE IN DISEASE

All cells rely on a complex interplay of both extracellular and intrac ellular signals to control their metabolism, growth and differentiatio n. Recent evidence shows that several free radicals and their derivati ves are able to act as signalling molecules. However, these molecules are inherently reactive towards biological materials such as proteins, lipids and DNA. In fact, the destructive power of these compounds app eals to be harnessed and used by organisms to destroy both invading pa thogens and tumour cells. Therefore, their use as signals seems to be a puzzle. Here, their production, Pole in signalling, and involvement in some diseases are discussed.