Two Americans win Nobel for illuminating how sense of smell works

Two Americans won the Nobel Prize in medicine Monday for discovering how people can recognize and remember an estimated 10,000 odors, from spoiled meat to a lover's perfume.

Dr. Richard Axel, 58, of Columbia University and Linda B. Buck, 57, of the Fred Hutchinson Cancer Research Center in Seattle revealed odor-sensing proteins in the nose and traced how they send their information to the brain.

The Nobel Assembly at the Karolinska Institute in Stockholm said it chose the pair for the $1.3 million prize not because of any practical payoff from the work, but simply because they enhanced understanding of "the most enigmatic of our senses."

For two scientists to single-handedly map one of the major human senses is unique in the history of science, Nobel assembly chairman Goeran Hansson said.

"It's pretty amazing to be able to sit here in the 21st century and reward discoveries that explain one of the human senses," he said.

Buck said she had not even known she was under consideration. "People have said things like, 'You should win the Nobel Prize,"' she said. "I feel very honored, of course."

Axel told Swedish Public Radio he had not been thinking about winning the prize. "I think about my science," he said.

In 1991, Axel and Buck jointly reported discovering a large family of genes devoted to producing different odor-sensing proteins, called receptors, in the nose. Before that, scientists could only guess at how many different receptors were needed to distinguish smells in the environment.

Scientists now know that people have a few hundred types of odor receptors, each of which can detect only a limited number of odors.

When a person sniffs perfume or fine wine, for example, a mix of different types of molecules flows over the receptors in the back of the nose. That activates an array of the receptors, but only those primed to respond to those particular molecules. The brain notes which receptors are activated, and interprets this pattern as the smell.

Since any given receptor can participate in more than one pattern, "you might have a rose and a skunk being recognized by some of the same receptors," Buck said.