The mystery of homochirality. What is important pharmaceutical Nobel in chemistry
The problem of synthesizing one of the two "mirror" molecules, which nature does itself, could not be solved for a long time. It was for this breakthrough that Nobel was given. The discovery of the laureates will also help in the creation of more effective drugs
The Nobel Prize in Chemistry in 2026 was awarded to scientists from France and Japan Henri Kagan and Kenso Soai "for discoveries that allowed to control the chemical reactions leading to homochirality." They managed to understand one of the most important issues of natural science - the asymmetry of living matter, say scientists interviewed by RBC. What is the essence of the achievements of Kagan and Soai and what it means for science and medicine - in our material.
What is homochirality and mirror molecules
Homochirality is “an amazing property of living nature” to use only one “hand” of molecules, although both are chemically possible, said biochemist, geneticist, microbiologist Igor Nikulin. The composition and order of these molecules are the same, but they cannot be combined in space. These pairs are called “mirror” variants, or enantiomers, adds Denis Vinnik, head of the Department of Physical Chemistry at MIPT.
“Imagine your hands. They are mirror images of each other, but they cannot be superimposed on top of each other - like the left glove does not fit on the right hand. Many molecules exist in two forms, like the right and left hand. In chemistry, they are called L-form (left) and D-form (right). Homochirality is when a system uses only one of these forms. For example, all the proteins in your body are built entirely from L-amino acids, explains Nikulin.
Another example that Vinnik already gives is the carvon. One of its forms smells of mint, and “mirror” – cumin. “The olfactory receptors distinguish them in the same way that a glove only fits your hand,” he said.
According to Nikulin, chemists previously could synthesize amino acids in the laboratory, but then they are obtained as a mixture: 50% left and 50% right. Life on Earth was chosen only by the left. Why? This is the main mystery of the origin of life, says Nikulin.
The essence of scientific discovery
As noted in the press release of the Nobel Committee, Kagan and Soai in the framework of their experiments sought through chemical reactions to obtain only one of the “mirror” variants of molecules, since, for example, applicable to pharmaceuticals, requires the enantiomer that has the desired effect.
The first step was taken by Kagan in 1986, when he managed to increase the proportion of one of the mirror molecules as a result of a chemical reaction. The experiments were continued by Soai, who in 2003 managed to practically derive only one of the two enantiomers. Such a result, apart from nature, until this moment no one could achieve.
“Over several successive cycles, the initial preponderance of one of the forms, even a negligible one, increases to an enantiomeric purity above 99.5%. This is the first example of asymmetric autocatalysis in organic reaction and convincing evidence that asymmetry can self-reinforce in a purely chemical system, without the involvement of biology.
Practical significance for science
The achievement of a Frenchman and a Japanese Nobel laureate is important for understanding the origin of life and for industrial chemistry, especially for pharmaceuticals. But don’t expect a “Nobel pill” tomorrow — Soai’s reaction works on a narrow class of compounds, he says.
Nikulin agrees with him. Homochirality is a fundamental knowledge, but “cures for diseases” are not directly created on its basis. However, understanding chirality is critical to pharmaceuticals, he points out. The discovery, awarded the Nobel Prize, is important in terms of developing the production of safe drugs for humans.
“A striking historical example is thalidomide [a sedative sleeping pill]. - RBC. One “hand” of this drug helped with toxicosis of pregnant women, and the other caused severe birth defects. Understanding chirality forces pharmaceutical companies to synthesize only the “correct” form, says Nikulin.
The drug thalidomide was synthesized in Germany in the 1950s, it was tested on animals (but not on pregnant individuals) and began to be used in the West as a means of suppressing morning sickness in pregnant women. The ban on use was introduced after it was found that the drug is the cause of the birth of children with underdeveloped hands and feet, as well as with other malformations.
The side effects caused by thalidomide led to the creation of special agencies to test drugs, including the Drug Safety Committee and the Medicines Act 1968 in the UK.
Receptors in the human body are also chiral, Nikulin continues. The medicine comes to them as a key to the lock. The “wrong” hand may simply not work or cause side effects, he explains. Understanding homochirality is a clue to how life chose the left hand to build proteins. This knowledge underpins modern pharmaceuticals, making drugs safer and more accurate, concludes Nikulin.
