Mark Zylka and Julie Hurt are recognized for their work on using injections of an enzyme called PAP into an acupuncture point behind the knees of mice relieved pain caused by inflammation for up to six days, much longer than normal acupuncture. PAP injections in mice with inflamed paws made the limbs less sensitive to heat and poking — but didn’t cause muscle weakness or other discernible side effects, the researchers found. Not only does PAP relieve inflammatory pain longer than acupuncture does, it also relieves nerve pain in mice, testing showed. Clinical studies in people have found that patients with nerve pain get worse after acupuncture, says Jon Levine, a professor of medicine at the University of California, San Francisco. Zylka says that a company may soon start testing the enzyme as a pain reliever for humans.