Differential oxidative damage to mitochondrial proteins during aging.

The level of mitochondrial protein oxidative damage, indicated by the protein carbonyl content, has been previously shown to increase with age. The objective of this study was to determine whether such age-associated damage is random or whether some proteins are relatively more susceptible. Mitochondrial proteins were analyzed by gel filtration. High molecular weight proteins were found to be relatively more oxidatively damaged during aging. Results are interpreted to indicate that protein oxidative damage during aging is not random. The question of the validity of the HPLC method for the measurement of protein carbonyls is discussed in light of a recent report questioning its reliability.