Symmetry 2010, 2(2), 1022-1032; doi:10.3390/sym2021022

Origin of Homochirality of Amino Acids in the Biosphere

Received: 21 January 2010; in revised form: 28 April 2010 / Accepted: 10 May 2010 / Published: 13 May 2010
(This article belongs to the Special Issue Symmetry of Life and Homochirality)
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract: Discussions are made concerning realistic mechanisms for the origin of L-amino acids in the biosphere. As the most plausible mechanism, it is proposed that a mixture of racemic amino acids in the prebiotic sea caused spontaneous and effective optical resolution through self crystallization, even if asymmetric synthesis of a single amino acid has never occurred without the aid of an optically active molecule. This hypothesis is based on recrystallization of a mixture of D,L-amino acids in the presence of excess of D,L-asparagine (Asn). The enantiomeric excess (ee) of each amino acid in the resulting crystals indicates that crystallization of co-existing amino acids with the configuration same as that of Asn took place, although it was incidental whether the enrichment occurred in L- or D-amino acids. In addition, the resulting ee was sufficiently high (up to 100%) to account for the predominance of L-amino acids on the earth.
Keywords: homochirality; L-amino acid; crystallization; chemical evolution; optical resolution; asymmetric synthesis; enantiomeric excess
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MDPI and ACS Style

Kojo, S. Origin of Homochirality of Amino Acids in the Biosphere. Symmetry 2010, 2, 1022-1032.

AMA Style

Kojo S. Origin of Homochirality of Amino Acids in the Biosphere. Symmetry. 2010; 2(2):1022-1032.

Chicago/Turabian Style

Kojo, Shosuke. 2010. "Origin of Homochirality of Amino Acids in the Biosphere." Symmetry 2, no. 2: 1022-1032.

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