Thursday, May 13, 1999 Published at 08:31 GMT 09:31 UK
Enzyme prolongs cell life
Enzyme keeps worm young
An enzyme that prolongs the life of animals has been discovered.
Studies of a microscopic roundworm suggest that the enzyme protects the cells from oxidation, a key element in the ageing process.
Biologists at New York's Columbia University found the enzyme in the cells of Caernorhabditis elegans, a tiny soil worm just one millimetre long.
Worms genetically-engineered to have high levels of the enzyme have been found to live two to four times longer than ordinary worms.
It is thought the enzyme, called cytosolic catalase, keeps the cell healthy by removing oxygen-based by-products of chemical reactions which can attack and damage cell components.
These reactions are normally confined to special regions inside the cell, where resident enzymes process the by-products the reactions produce.
Cytosolic catalase patrols the whole cell, mopping up oxidants wherever it finds them. Although cytosolic catalase has been found in plants and yeast before, this is the first time it has been seen in animal cells.
"Our explanation for the long life spans in the mutant worms is that the catalase is protecting the cells from oxidative damage and keeping them healthy." said Martin Chalfie, Professor of Biological Sciences at Columbia.
Professor Chalfie says there is no evidence yet that any particular gene controls life span in worms, or in humans. His research shows that cytosolic catalase simply protects cells from oxidative damage.
Because the cells in adult roundworms do not divide, the research may be applicable to similar cells in humans, such as nerve cells. Damage from oxidation has been implicated in Alzheimer's disease and motor neurone (or Lou Gehrig's) disease.