Comment by PowerElectronix
11 hours ago
>Other than life itself, no one had achieved this feat.
Yeah, when you put it that way it sounds pretty impresive.
11 hours ago
>Other than life itself, no one had achieved this feat.
Yeah, when you put it that way it sounds pretty impresive.
As I understand it, the chirality problem is one of the big ones in abiogenesis - the beginning of life. How does some initial series of inorganic "accidents" lead to life? The necessary chemistry has to give the right chirality.
But maybe someone better informed can explain... I've only heard James Tour ranting about it
Chemist here. I read this and thought it was either lies or propaganda. But after a while of pondering , it would say that the word "homochiralic" (creation-from-nothing) does a lot of heavy lifting here to make their claim technically true, if at all:
Asymmetric synthesis was already well established before 1995. Chemists like Knowles, Noyori, Sharpless, and Evans could routinely produce highly enantioenriched molecules using chiral catalysts or auxiliaries.
What made Soai's reaction different was that it did not require an external chiral source. The chiral product catalyzes its own formation, so a tiny random imbalance can be amplified into a very large enantiomeric excess.
Other examples of abiotic asymmetry, such as Pasteur's crystallization experiments and circularly polarized light, were also known earlier.
So the Nobel press release is best understood as shorthand: Soai did not discover asymmetric synthesis, but demonstrated a remarkable form of self-amplifying, spontaneous chiral symmetry breaking in an abiotic chemical system.
That helps a lot! I'm a novice learning about enzymatic synthesis. I'm not there yet, but my assumption is the target molecules (And reactants/intermediate-products) will all have specific chiralities, unlike the chemical-synthesis ones which may produce 50/50. Everything in my data structures (And the pubchem CID / ChEBI ids they reference) are chiral.
Is it explained why, in this drawing, the right catalyst forms at a higher rate than the left? Or put another way why left/right catalyst gets formed at a higher rate than right? I’m trying to understand the why behind the amplification effect.
All reagents are symmetric, so how do you design a reaction where you produce more left or right? So starting from purely symmetric reagents and catalysts, how do you produce asymmetry?
When the chirality of the product is an autocatalyst to its own chirality. So if your reaction starts off with a little more left than right due to molecular randomness, the left is an autocatalyst which means there is a runaway process and you end up at the end of the reaction with a lot more left than right.
If you repeat the reaction from scratch, it is random if you end up with a left product or a right product. But the product of your reaction is not a 50-50 mix left-right! I.e. you created asymmetry in your solution from purely symmetric solvents.
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