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Updated: May 22, 2026
09:14
Enzymatic Cascade Reactions for the Synthesis of Chiral Amino Alcohols from L-lysine
Published on: February 16, 2018
Chiral polymerization in open systems from chiral-selective reaction rates
Marcelo Gleiser1, Bradley J Nelson, Sara Imari Walker
1Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755, USA. mgleiser@dartmouth.edu
Summary
Prebiotic homochirality may arise from subtle chiral-selective reaction rates in polymerization networks. Even small biases in reaction speed can lead to significant chiral excess, suggesting a plausible origin for life's molecular asymmetry.
Area of Science:
- Astrobiology
- Chemical Evolution
- Origin of Life Studies
Background:
- The origin of homochirality (the prevalence of one enantiomer) in biomolecules is a fundamental question in the origin of life.
- Existing models often invoke specific chiral catalysts or external influences.
- This study explores an alternative: homochirality arising solely from intrinsic reaction rate differences.
Purpose of the Study:
- To investigate if chiral-selective reaction rates alone can generate prebiotic homochirality.
- To determine the required level of chiral bias in reaction rates for significant chiral excess.
- To assess the plausibility of this mechanism under early Earth conditions.
Main Methods:
- Modeling an open network of polymerization reactions with chiral-selective rate parameters.
- Employing a statistical approach by varying mean rates and root-mean-square dispersion.
- Analyzing the resulting chiral excess as a function of chiral bias in reaction rates.
Main Results:
- Moderate to high levels of chiral excess can be achieved with surprisingly small chiral bias (below 10%) in reaction rates.
- The findings are robust across variations in mean rate values and dispersion.
- Autocatalysis and enantiomeric cross-inhibition are not required for homochirality generation.
Conclusions:
- Homochirality could have emerged on early Earth through intrinsic, moderate chiral selectivity in reaction rates.
- This mechanism offers a plausible pathway independent of strong external chiral influences.
- Environmental factors affecting reaction rates further support the feasibility of this scenario.
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