“for the discovery of non-linear effects and autocatalysis in asymmetric organic synthesis”

Life’s chemistry is what chemists call homochiral, after the Greek words for “same” and “hand”. Like hands, all amino acids exist as two mirrored variants, but only one of them is found in the proteins in your cells. The other is rarely found in nature.

For a long time, chemists wondered how homochirality can emerge. When they began to experiment with chemical reactions that can form two mirrored molecules, they always obtained equal proportions of both in their test tubes. However, chemists strived to produce only one of these mirror images, because in the development of molecules that will interact with living beings – such as in pharmaceuticals – only one mirror image will have the desired effect.

The Nobel Prize in Chemistry 2026 recognises discoveries that have enabled chemists to drive chemical reactions that lead to homochirality.

“Henri Kagan and Kenso Soai have provided a solution to a chemical mystery that is over a century old: how homochirality can emerge spontaneously. The chemical reactions they have developed are spectacular,” says Heiner Linke, chair of the Nobel Committee for Chemistry.

In a way Kenso Sai work implements this.

This is basically kind of a process I remember being suggested even before their works (I learned about it in the early eighties, and I strongly doubt it was a fresh one then). The idea is that of a self-enforcing change: imagine you have a bag of black and white marbles. You draw three at random. If they are identical - return them. If one is different from two others: change its color and return three identical marbles to the bag. This is an unstable equilibrium - initially nothing happens, but at some point for purely statistical reasons one color starts to dominate and then it is kind of a runaway reaction, everything changes quickly either to black, or white.

In a way Kenso Sai work implements this.

And generally speaking: their discovery doesn't "solve" anything. It proves the solution can exist and can be rooted in a natural process. But none of the examples they found seems "practical" - as in "possible to appear in a typical mix of naturally existing reagents we expect to see in the primordial soup".

No.

And generally speaking: their discovery doesn't "solve" anything. It proves the solution can exist and can be rooted in a natural process. But none of the examples they found seems "practical" - as in "possible to appear in a typical mix of naturally existing reagents we expect to see in the primordial soup".

Soai's work demonstrates how homochirality can be self-amplifying, rendering the single-origin of chiral biomolecules plausible. Since the primordial soup existed in the primordial cauldron of the ancient Earth, I wonder if there existed certain minerals with a surface structure that allowed for stereospecific chemistry. Here I refer to how the active site of enzymes can be stereospecific due to their three-dimensional structure, although these active sites also involve asymmetric biomolecules, which challenges the self-consistency of the idea.

If we assume there exists / was such a mineral with a stereospecific surface structure, it still begs the question of why that surface structure was that orientation. As far as I know, it doesn't matter if biology is left or right handed, as long everything remains consistent. That is, if we inverted the configuration of all molecules everywhere at once, it would be indistinguishable in behavior. This necessitates only an initial, arbitrary bias for symmetry, which seems conceptually plausible in the context of geology ... but I'm out of my depth here.

I started to wonder though: many reactions tend to "keep" chirality of reactants (or to reverse it, depending on the mechanism, but that means they still belong to the same pathway). Technically that could mean initial existence of two separate "kingdoms", L and D, competing for the resources. Once a member of one of the "kingdoms" evolves (at random) to become autotrophic and produce molecules of one type, "kingdom" takes over, as resources of one type become abundant. After that whole system evolves around one chirality, only enforcing its dominance. Pure speculation.