Hitz and Luisi

The relation between the single-chain homochiral amplification and the dilution is given in Figure 4.10 (Hitz and Luisi, 2004). Of course the l oligomers would become extremely diluted in the total mixture, so that from a practical point of view this 100% e. e. is not very useful. One would need some specific methods to extract... 

The observation that chains tend to grow in a homochiral way, is also true for polypeptides. For example in the polymerization of NCA-activated a-amino acids there is a natural tendency to form homochiral chains (Blocher et al., 2001 Hitz and Luisi, 2004). In particular when a racemic mixture of NCA-activated amino acids is polymerized, a mixture of chain lengths up to heptamers or decamers is obtained, which, as expected, is a racemate. However, in these products there is a significant excess of homochiral stretches. One typical result is shown in Figure 4.11. 

Blocher, M., Hitz, T., and Luisi, P. L. (2001). Stereoselectivity in the oligomerization of racemic Tryptophan A-Carboxyanhydride (NCA-Trp) as determined by isotopic labelling and mass spectrometry. Helv. Chim. Acta, 84, 842-8. 

Hitz, T. and Luisi, R L. (2004). Spontaneous onset of homochirality in oligopeptide chains generated in the polymerization of IV-carboxyanhydride amino acids in water. Orig. Life Evol. Biosph., 34 (1-2), 93-110. 

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