People hoping to successfully quit smoking may soon get some help from a nicotine-chomping natural enzyme, researchers say.
By consuming nicotine in a smoker's system before it reaches the brain and delivers its desired "reward," the enzyme could offer significant improvement over existing smoking cessation options such as gum, patches and pills, they suggest.
Such current options fail in 80 to 90 percent of smokers, they point out.
Long-term efforts to create such an enzyme have met with little success, but nature has presented researchers with an enzyme called NicA2, found in bacteria known as Pseudomonas putida.
Found in soils from tobacco fields, the bacteria depends on nicotine as its only source of the carbon and nitrogen it needs to live.
"The bacterium is like a little Pac-Man," says Kim Janda, a chemist at The Scripps Research Institute in La Jolla, California. "It goes along and eats nicotine."
In an experiments to test the enzyme as a possible aid to quitting smoking, the researchers added nicotine to a blood sample at a level corresponding to smoking one cigarette, then added the NicA2 enzyme.
The half-life of the nicotine -- a measure of how long it remained active in the blood -- was reduced from 2 to 3 hours to 9 to 15 minutes, the researchers reported in the Journal of the American Chemical Society.
Higher doses, along with some chemical alterations, could bring an even faster reduction, perhaps keeping nicotine in the blood from ever reaching the brain, they suggest.
To see if the enzyme could be a viable drug candidate, they tested it to see if it would remain stable, which it did for up to 3 weeks at 98 degrees -- body temperature.
"Hopefully we can improve its serum [blood] stability with our future studies so that a single injection may last up to a month," says Song Xue, a Scripps graduate student and first author of the new study.
The scientists also tested to see if the enzyme produced any toxic byproducts as it consumed the nicotine, and found none.
"Our research is in the early phase of drug development process, but the study tells us the enzyme has the right properties to eventually become a successful therapeutic," says Janda.