title: Protein oxidation and aging.
abstract: Organisms are constantly exposed to various forms of reactive oxygen species (ROS) that lead to oxidation of proteins, nucleic acids, and lipids. Protein oxidation can involve cleavage of the polypeptide chain, modification of amino acid side chains, and conversion of the protein to derivatives that are highly sensitive to proteolytic degradation. Unlike other types of modification (except cysteine oxidation), oxidation of methionine residues to methionine sulfoxide is reversible; thus, cyclic oxidation and reduction of methionine residues leads to consumption of ROS and thereby increases the resistance of proteins to oxidation. The importance of protein oxidation in aging is supported by the observation that levels of oxidized proteins increase with animal age. The age-related accumulation of oxidized proteins may reflect age-related increases in rates of ROS generation, decreases in antioxidant activities, or losses in the capacity to degrade oxidized proteins.
authors.affiliation: National Heart, Lung, and Blood Institute, National Institutes of Health, Biochemistry and Biophysics Center, MSC-8012, Bethesda, MD 20892-8012, USA. erstadtman@nih.gov
authors.forename: Earl R
authors.initials: ER
authors.lastname: Stadtman
mesh_terms: D000375:Aging / Q000502:physiology*; D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D003432:Cross-Linking Reagents / Q000378:metabolism; D006801:Humans; D008239:Lysine / Q000378:metabolism; D008715:Methionine / Q000031:analogs & derivatives / Q000378:metabolism; D010084:Oxidation-Reduction; D011506:Proteins / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D000596:Amino Acids; D003432:Cross-Linking Reagents; D011506:Proteins; D017382:Reactive Oxygen Species; D008715:Methionine; D008239:Lysine; C013111:methionine sulfoxide