Bio-Oxidation <br /> Dr. Asma'a Hassan Mohamed<br /> Oxidation is defined as the process of electron loss, while the reduction as the process of electron gain therefore, both processes occur simultaneously and because of the body has a complex biological system and multiple chemical reactions, oxidation and reduction is therefore an important process involved in this system. Oxidation depends on the participation of oxygen and its compounds as the essential element needed by the biological systems in the processes of cellular respiration to release energy in the form of ATP molecules in the mitochondria by a special enzymatic chain. Bio-oxidation is defined as the interaction between compounds or molecules that have one or more free electrons in their outer envelopes with cellular components causing disruption of the cellular system, oxidation is also useful in the oxidation of compounds to liberate energy and enter into a number of cellular activities, it has harmful aspects are the main cause of some health problems and diseases that affect human such as development of heart disease, darkening of eye lens, many genetic disease, and tumors. <br /> The harmful effects of oxygen are due to its oxidative activity in its chemical compound, these compounds tend to give or lose an electron and are the so-called free radicals that form in the body as a results of some vital processes or as a results of exposure to some external factors. The free radicals are defined as molecules or atoms that contain an individual numbers of electrons that gain a degree of chemical activity, free radicals are formed when an ionic bond splits or breaks between two atoms so that each atom takes an electron and turns into a free radical or the results of the interaction of two types of free radicals involvement in an enzymatic reaction to be another, free radicals are formed in the body as a by-products of biological processes and cellular activities and are either enzymatic or non-enzymatic reactions. Free radicals perform important processes in the body such as the release of energy, destruction of microbes, and in some enzymatic manufacturing pathways for example, low concentrations of free oxygen radicals play an important role in cellular response and vital systems of cellular signals, but when they increases above the normal limits cause destruction of cellular molecules such as fats, proteins, and nucleic acids causing a number of diseases. The toxic effects of oxygen have been observed by Gershman, who developed the theory of free radicals of oxygen toxicity in 1954, in which oxygen toxicity was shown to be the result of its reduced form, is the same year using an MRI device, there was a weak signals for an electron due to free radicals in various biomaterials, the world of free radicals in body fluids was observed in 1956 when Harman proposed the importance of free radicals in aging and the studies continued to show the importance of free radicals in the life system. In 1969, scientists McCord and Friedovich discovered superoxide dismutase (SOD) enzyme they demonstrated the importance of free radicals in the life system, and in 1977 Mittal and Murad proved the role of hydroxyl radical in stimulating guanylate cyclase enzyme to form cyclic guanosine monophosphate (cGMP), then t he research were followed to search about positive and negative role of free radicals.