Abstract
Iron in the free ionic state is very reactive as it generates and reacts with free radicals of the type HO, LO, LOO', O2 and C. These are highly reactive species and participate in reactions that are mostly deleterious to cell components, including DNA, proteins and lipids. In association with a complexing agent such as bleomycin, Fe2+ degrades DNA into soluble nucleotides'. In the presence of oxygen and a reducing agent, DTT, Fe2+ inacativates enzymes by peptide bond cleavage2. Chelated to ADP, Fe2+ promotes peroxidation of polyunsaturated fatty acids and breakdown of membranes3. These do not occur in normal cells as they are kept under check by antioxidant devices, and more importantly by keeping free iron concentration low.
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