Agents such as nerve gas can cause death by suffocation by disrupting signals between nerve and muscle cells. The gas inhibits acetylcholinesterase, an enzyme responsible for the breakdown of a chemical messenger responsible for muscle control, which is how it causes much of its ill effects. Existing drugs for the treatment of nerve agent poisoning are only effective when faced with small doses of the nerve gas, and are known to have serious side effects, so some researchers are looking to enzymes that occur within our bodies. Using enzymes breaks down the nerve agents before they have a chance to bind to the body's chemical messenger and prevents damage. However, naturally-occurring enzymes are too slow to be effective.