OXIDATIVE STRESS AND LIVING CELLS

The review deals with the effects of reactive oxygen species, both rad ical and nonradical (e.g. hydrogen peroxide), on cells and organisms. The chemical and biochemical aspects include description of individual reactive oxygen species, chemical reactions giving rise to them, thei r interconversions and interactions with metals (Fe2+, Cu2+, Cu+) and other substances (scavengers, antioxidants). The biological aspects co ncern the specific features and locations of cellular enzyme systems i nvolved in radical production and/or removal. Major harmful effects of the species on the molecular (protein oxidation, lipid peroxidation, damage to DNA) and cellular level (effect on signal transduction, on c ell membrane functions and on gene expression) are surveyed. Methods w hereby cells and organisms cope with the onslaught of these reactive s pecies are reviewed as well as implications for plant, animal and huma n health.