Published: 11:22 PM, 07 October 2026
Kagan, Soai win Nobel chemistry prize
Scientists Henri Kagan and KensoSoai won the 2026 Nobel Prize in Chemistry for solving a long-standing mystery surrounding asymmetric "mirror image" molecules, in work that has proved important for pharmaceutical manufacturing, the award-giving body said on Wednesday.
Soai, 76, is Japanese, while Kagan, 95, is French. Their research built on discoveries by 19th-century French chemist Louis Pasteur.
"This is the most exciting day in my life, I am very glad to share this prize with professor Henri Kagan," Soai said by phone during the Nobel Prize press conference. He said he had been out shopping when he learned he had won the award, Reuters reports.
The Nobel committee was still trying to reach Kagan to inform him of the prize.
Many molecules essential to life exist in two forms that are mirror images of one another, much like left and right hands. Yet living organisms almost exclusively use one version, a phenomenon known as "homochirality" that has puzzled chemists for more than a century.
Kagan and Soai were honoured for discoveries showing how chemical reactions can be controlled to favour one molecular form over its mirror image. The work has provided important tools for designing chemical reactions used in pharmaceutical production.
"The left-handed version of the drug can have one effect, and the right-handed version can have another effect, and then we need methods for selectively preparing them," said Peter Somfai, a member of the Nobel Committee for Chemistry.
"In developing such methods the findings of this year's laureates are important. They provided powerful tools for that," he said.
The scientific puzzle can be traced back to Pasteur, who studied tartaric acid, a substance important in winemaking. He found that bacteria fermented only one of its two forms, showing that the substances could have different properties.
The challenge of producing the desired form of a chiral substance remained unresolved until Kagan and Soai developed asymmetric reactions capable of producing an excess of one molecular form.
The importance of controlling molecular handedness was highlighted by the thalidomide scandal of the early 1960s, when thousands of children were born with birth defects after their mothers took the sedative. Researchers later found that one mirror-image form of the active substance was responsible for the harmful effects.
The chemistry prize is the third Nobel awarded this week, following the medicine and physics prizes announced on Monday and Tuesday.
The laureates will receive their medals from Sweden's King Carl XVI Gustaf at a ceremony in Stockholm on Dec 10, the anniversary of Alfred Nobel's death. They will also share 12 million Swedish crowns ($1.2 million).
