Quitting smoking is tough—so tough that only about 5 percent of smokers who try to quit in a given year actually succeed. Medications can double those odds—which still leaves a high failure rate. And a promising vaccine, meant to arouse an immune response to nicotine, could not beat a placebo in clinical trials. But researchers haven't given up on a vaccine yet. Instead of revving up the immune system, though, they've come up with a new idea: why not use an enzyme to break down nicotine—before it gives you a buzz?

"For almost 50 years there's been reports of bacteria that can actually use nicotine to thrive on." Kim Janda, a chemist and immunologist at The Scripps Research Institute. "The bacteria uses nicotine as its sole source of carbon and nitrogen."

It does the trick with a nicotine-chomping enzyme. So Janda and his colleagues added the enzyme to mouse serum, doped with a cigarette's worth of nicotine. The enzyme was stable at human body temperature—and was able to cut the half-life of nicotine from a couple hours to less than 15 minutes—that is, it greatly accelerated nicotine’s disappearance. The study is in the Journal of the American Chemical Society. [Song Xue et al, A New Strategy for Smoking Cessation: Characterization of a Bacterial Enzyme for the Degradation of Nicotine]

But Janda says the enzyme isn't ready for primetime yet. It's bacterial—so "you're going to get an immune response, immune surveillance from it." And right now, the other important half-life, that of the enzyme in serum, is only 3 days. So it won’t stick around long enough to be an effective vaccine. "A month would be great, a week or two would also be reasonable." While the researchers work out the kinks, smokers will have to rely on the tried-and-true methods of quitting: counseling, medication or good old cold turkey.

—Christopher Intagliata

[The above text is a transcript of this podcast.]