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Experiments on the abiotic amplification of optical activity
Origins of Life
|March 1, 1981
Summary
Abiotic chiral physical forces can generate optical activity in amino acids. Repetitive polymerization and hydrolysis steps may have enhanced enantiomeric excesses on early Earth, forming optically enriched polypeptides.
Area of Science:
- Astrobiology
- Organic Chemistry
- Biochemistry
Background:
- Previous research explored abiotic optical activity generation in amino acids using chiral physical forces.
- Initial enantiomeric enrichments were found to be low, necessitating further investigation.
Purpose of the Study:
- To investigate methods for abiotically enhancing low enantiomeric excesses of amino acids.
- To explore potential mechanisms for the origin of homochirality in biomolecules.
Main Methods:
- Partial polymerization of D/L-mixtures of leucine N-carboxy anhydride (NCA).
- Stereoselective hydrolysis of leucine-based polymers.
- Comparative analysis of leucine and valine NCA polymerization behavior.
Main Results:
- Leucine NCA mixtures yielded enantiomerically enriched polymers upon partial polymerization.
- Valine NCA mixtures exhibited opposite behavior to leucine NCA.
- Leucine polymers demonstrated stereoselective hydrolysis, further increasing enantiomeric enrichment.
Conclusions:
- A cyclical process of partial polymerization and hydrolysis is proposed as a viable mechanism for abiotic enrichment of polypeptides.
- This mechanism offers a potential pathway for the origin of optical activity in biomolecules relevant to early life.
- The findings contribute to understanding the prebiotic synthesis of chiral molecules.