[Toxicologic importance of iron and copper atoms and their relation to reactive oxygen metabolites]

Free radicals are, on the one hand, necessary for the physiological function of some systems but, on the other had, they play an important pathologic role. The formation of free radicals can be the result of various conditions and can initiate various diseases. Their formation may also be a consequence of certain pathological state of the organism. In this way generated free radicals can cause in the secondary to the damage organism. The metabolism of free radicals is significantly influenced by transition metals. These metals are present in the organism at given oxidative state chelated in the proteins. In this form the metalloproteins to have unique catalytical and redox properties. The transition metals are a part of an active centre of many enzymes. Iron and copper are the predominant transition metals in human organism. These metals are vitally important, but if present in high concentration, in unsuitable oxidative state and at improper site, they can catalyse the formation of highly toxic reactive metabolities of oxygen, for example hydroxyl radicals. The toxic damage may be direct if the metals are present in high oxidative state Fe(IV) or Fe(V). These "ferryl" compounds are strong prooxidants. The organism maintains the iron metabolism in equilibrium. If the iron plasma concentration reaches 40 micro-mol/L, it is a sign, that iron is released from physiological protein structures and forms so called "catalytically active iron". In this form iron can be involved in Fenton reaction in which hydroxyl radical is formed. The article discussed the toxic effect of "catalytically" active iron at a given oxidative state with its influence on some diseases.