Aging and protein oxidative damage.

The hypothesis that aging is associated with the accumulation of oxidative damage was tested in the adult male housefly by monitoring the loss of membrane protein -SH groups, and activities of glucose-6-phosphate dehydrogenase and alcohol dehydrogenase, the cytosolic enzymes that are particularly susceptible to oxidative damage. Membrane protein -SH content and activities of these enzymes decreased with age and were correlated with the life expectancy or physiological age rather than the chronological age of the flies. Because the experimentally-induced loss of membrane protein -SH groups has a demonstrable deleterious effect on a variety of cellular functions, such damage during aging can be hypothesized to contribute to the physiological attrition associated with senescence.