Hi, thanks for the abstract. I've been interested in homochirality ever since a heated discussion with a Mormon who, rather cleverly, used the homochirality argument to 'prove' that life must have had a creator - since if it arose spontaneously there should be equal amounts of left and right-handed amino acid stereoisomers. At the time all I could say, lamely, was that there had to be some kind of scientific explanation but I had to agree with him that those that were available at the time were a little bit thin to say the least. Perhaps the abstract sheds some light on the problem, giving an alternative to asymmetric amplification in autocatalytic networks although a skeptic could argue that it is a chemical curiosity and not all that relevant since quite high concentrations are needed to have a solid-liquid equilibrium.

Andrew

Nature 441, 621-623 (1 June 2006) | doi:10.1038/nature04780; Received 21 November 2005; Accepted 30 March 2006
Thermodynamic control of asymmetric amplification in amino acid catalysis
Martin Klussmann Hiroshi Iwamura Suju P. Mathew, David H. Wells, Jr Urvish Pandya, Alan Armstrong and Donna G. Blackmond
Abstract
Ever since Pasteur noticed that tartrate crystals exist in two non-superimposable forms that are mirror images of one another—as are left and right hands—the phenomenon of chirality has intrigued scientists. On the molecular level, chirality often has a profound impact on recognition and interaction events and is thus important to biochemistry and pharmacology. In chemical synthesis, much effort has been directed towards developing asymmetric synthesis strategies that yield product molecules with a significant excess of either the left-handed or right-handed enantiomer. This is usually achieved by making use of chiral auxiliaries or catalysts that influence the course of a reaction, with the enantiomeric excess (ee) of the product linearly related to the ee of the auxiliary or catalyst used. In recent years, however, an increasing number of asymmetric reactions have been documented where this relationship is nonlinear1, an effect that can lead to asymmetric amplification. Theoretical models have long suggested that autocatalytic processes can result in kinetically controlled asymmetric amplification, a prediction that has now been verified experimentally and rationalized mechanistically for an autocatalytic alkylation reaction. Here we show an alternative mechanism that gives rise to asymmetric amplification based on the equilibrium solid-liquid phase behaviour of amino acids in solution. This amplification mechanism is robust and can operate in aqueous systems, making it an appealing proposition for explaining one of the most tantalizing examples of asymmetric amplification—the development of high enantiomeric excess in biomolecules from a presumably racemic prebiotic world.