STOCKHOLM — Henri B. Kagan and Kenso Soai won the Nobel Prize in chemistry Wednesday for their efforts to resolve mysterious mirror images in chemical molecules.

Many molecules of life come in versions that look alike but aren’t exactly identical, like right and left hands. One mirror-image of the chemical carvone smells like mint, for example, while the other has a whiff of caraway.

When designing drugs to treat diseases, scientists want to be choosy about which mirror-image they’re getting. They want the version of a molecule that’ll treat a cold, not the kind that’ll make the sniffles worse.

Kagan and Soai found ways to make chemistry pick a side, designing and manipulating reactions to produce the desired mirror-image.

“This is probably the coolest experiment in organic chemistry,” said Peter Somfai, a member of the Nobel Committee for Chemistry. “Taken together, the groundbreaking discoveries by Henri Kagan and Kenso Soai have reshaped our understanding of molecular chirality — how it is created, amplified and transmitted.”

“Homochirality” comes from the Greek words for “same” and “hand.”

“It might be difficult to say that this drug, or that drug, was developed using this,” Somfai said. “I would say all of them, because we use this as a tool, we use this as an understanding, how to develop catalysts, how they function.”

Kagan, 95 years old and born in France, is affiliated with Université Paris-Sud in Orsay, France, and Soai, born in Japan, with the Tokyo University of Science.

Kagan’s research dates back to the 1980s, when he found a new way to manipulate chemical reactions.

“I’m very excited to receive the very nice news,” Soai told the committee and journalists by phone. “Of course this is one of the most exciting days in my life.”

He said he was shopping near his home when he was reached by the Nobel committee.

The Royal Swedish Academy of Sciences announced the winner in Stockholm.

Last year, three scientists won the chemistry Nobel for their development of new molecular structures that can trap vast quantities of gas inside, laying the groundwork to potentially suck greenhouse gases out of the atmosphere or harvest moisture from desert environments.

This year’s prizes began with the Nobel for medicine, awarded Monday to three scientists whose work led to a tool that uses light to help unravel how the brain works. The physics award Tuesday recognized a scientist’s efforts to demystify a rare group of neutrinos.

The literature prize is set to be awarded Thursday. After Friday’s peace prize is awarded, the Nobel Memorial Prize in Economic Sciences will be announced Monday.

The prize money this year is 12 million Swedish kronor (about $1.2 million), whether for an individual, a small group of laureates or an organization.

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This story has been corrected to clarify that Kagan, and not Soai, is 95 years old.

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Ramakrishnan reported from New York and Dazio reported from Berlin. Associated Press journalist Alexa St. John contributed from Detroit.

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AP Nobel Prizes: https://apnews.com/hub/nobel-prizes