Oxidatively modified proteins are continuously produced in cells by reactive oxygen and
nitrogen species generated as a consequence of aerobic metabolism. During periods of
oxidative stress, protein oxidation is significantly increased and may become a threat to cell
survival. In eucaryotic cells the proteasome has been shown (by purification of enzymatic
activity, by immunoprecipitation, and by antisense oligonucleotide studies) to selectively
recognize and degrade mildly oxidized proteins in the cytosol, nucleus, and endoplasmic …