A new study has found that when the body fights oxidative damage, it calls up a reservist enzyme that protects cells – but only if those cells are relatively young.Biologists at USC discovered major declines in the availability of an enzyme, known as the Lon protease, as human cells grow older.
The finding may help explain why humans lose energy with age and could point medicine toward new diets or pharmaceuticals to slow the aging process.
The researchers showed that when oxidative agents attack the power centers of young cells, the cells respond by calling up reinforcements of the enzyme, which breaks up and removes damaged proteins.
As the cells age, they lose the ability to mobilize large numbers of Lon, the researchers reported in The Journals of Gerontology.
Senior author Kelvin J. A. Davies, a professor at the USC Leonard Davis School of Gerontology, used a war analogy to explain that no "standing army" of Lon protease can endure an attack by invading oxidants without calling up reserves.
"Once the war has started, what's your capacity to keep producing … to protect your vital resources and keep the fight going?" he asked.
Since aging is the longest war, the USC study suggests a more important role for the reservist enzyme than previously known.
Lon protects the mitochondria – tiny organisms in the cell that convert oxygen into energy. The conversion is never perfect: Some oxygen leaks and combines with other elements to create damaging oxidants.
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