| Abstrakt: |
A detailed analysis of literary data concerning the oxidative modification of proteins by active oxygen species was carried out. It was shown that intermediate products of molecular oxygen reduction, e.g., superoxide anion radical, hydrogen peroxide and hydroxyl radical, can induce the inactivation of enzymes in vitro as a result of oxidative modification of certain amino acid residues necessary for the maintenance of native properties of the enzyme. In some cases modification of enzymes results in their degradation by proteolytic enzymes. Besides, some enzymes catalyzing the interconversions of active oxygen species (catalase superoxide dismutase, cytochrome P-450) are also inactivated in the course of catalysis under the oxidative action of active oxygen species. It was assumed that the oxidative modification of proteins appears to be one of the mechanisms which control their degradation in the cell. The hydroxyl radical oxidizing the amino acid residues located in the vicinity of the site of its synthesis is a direct modifying species. The superoxide anion radical and hydrogen peroxide are hydroxyl radical precursors and are responsible for the transport of oxidizing equivalents in the cell. |
