They replicated something only life can do: The discovery behind Chemistry Nobel

Your left and right hands are mirror images of each other, but you cannot perfectly fit a left-hand glove onto your right hand.Chemistry has a similar problem. Many molecules come in two mirror-image forms, and while they contain the same atoms, they can behave very differently inside living organisms.The 2026 Nobel Prize in Chemistry has been awarded to Henri B Kagan and Kenso Soai for discovering how chemical reactions can be made to favour one of these two molecular “hands”. An illustration of the 2026 Nobel Prize in Chemistry winners. (Photo: Nobel Prize) Their work helps explain a fundamental mystery of life, and why living organisms overwhelmingly use one version of certain molecules, and gives scientists a way to deliberately make the version they need. This is particularly important in making medicine, where the two mirror-image forms of the same molecule can behave very differently in the body.WHY DO MOLECULES HAVE MIRROR IMAGES?Some molecules come in two forms that are like a person's left and right hands. They contain the same parts, but their structures are arranged as mirror images and cannot simply be placed on top of each other to match.Amino acids, for example, exist in two such forms. They are the building blocks of proteins, but living organisms overwhelmingly use just one of the two versions. Chemists call this one-sidedness “homochirality”. (Photo: Johan Jarnestad/The Royal Swedish Academy of Sciences) For more than a century, scientists wondered how this preference could arise.When they tried to make molecules that could exist in either mirror-image form, their chemical reactions generally produced both versions in equal amounts.HOW DID THE LAUREATES SOLVE THE PROBLEM?Kagan made the first major breakthrough in 1986 when he discovered a way of manipulating chemical reactions so that one mirror-image form could be produced in a greater amount than the other.Soai took the next crucial step in 1995, describing a chemical reaction that had the potential to become completely one-sided. (Photo: Johan Jarnestad/The Royal Swedish Academy of Sciences) Eight years later, in 2003, he succeeded in creating a reaction in which only one of the two possible mirror-image forms was produced.The Academy said that no one other than life itself had achieved this before.This was possible because of chemical effects in which a reaction can reinforce its own outcome, allowing a small initial imbalance to grow. (Photo: Johan Jarnestad/The Royal Swedish Academy of Sciences) WHY IS THE ACHIEVEMENT SIGNIFICANT?The discovery showed chemists how one mirror-image form can emerge and dominate rather than remaining mixed with its counterpart.This discovery alone could have some major implications for medicine.When scientists design molecules that interact with living organisms, choosing the right mirror-image form can determine whether a compound produces the desired effect.Kagan and Soai's discoveries have therefore become important in designing chemical reactions used to manufacture pharmaceuticals, while also solving a fundamental question about the unusual one-sided chemistry of life.- Ends