title: [The two faces of reactive oxygen species].
abstract: Oxidative stress has been implicated in playing a crucial role in aging and in the pathogeneses of a number of diseases, including neurodegenerative disorders such as Alzheimer's disease. Oxidative stress occurs due to an imbalance in prooxidant and antioxidant levels. Reactive oxygen species (ROS) are highly reactive and may modify and inactivate proteins, lipids, DNA, and RNA and induce cellular dysfunctions. To prevent free radical-induced cellular damage, the organism has developed a defense mechanism, the antioxidative system. This system includes antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSHPx), and glutathione reductase (GSSGR) and low-molecular antioxidants such as glutathion and plasma proteins. Glutathion plays a key role in maintaining the physiological balance between prooxidants and antioxidants. Plasma proteins can inhibit ROS generation and lipid peroxidation by chelating free transition metals. The major exogenous antioxidants are vitamins E, C, and A.
authors.affiliation: Instytut Immunologii i Terapii Doświadczalnej PAN im. L. Hirszfelda we Wrocławiu. zablocka@iitd.pan.wroc.pl
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Zabłocka
authors.forename: Maria
authors.initials: M
authors.lastname: Janusz
mesh_terms: D000375:Aging / Q000378:metabolism*; D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D001205:Ascorbic Acid / Q000378:metabolism; D005609:Free Radicals / Q000378:metabolism*; D005978:Glutathione / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000378:metabolism; D005980:Glutathione Reductase / Q000378:metabolism; D006801:Humans; D007633:Keratins / Q000378:metabolism; D009420:Nervous System / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013482:Superoxide Dismutase / Q000378:metabolism; D014801:Vitamin A / Q000378:metabolism; D014810:Vitamin E / Q000378:metabolism
chemical_list: D000975:Antioxidants; D005609:Free Radicals; D017382:Reactive Oxygen Species; D014801:Vitamin A; D014810:Vitamin E; D007633:Keratins; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D005980:Glutathione Reductase; D005978:Glutathione; D001205:Ascorbic Acid