Partial racemization of amino acids in meteorites: implications for their possible modes of origin

摘要

The structural proteins of all living organisms consist of twenty amino acids, nineteen of which have asymmetric centers. In living organisms these amino acids occur almost exclusively in the L-configuration. Protein amino acids synthesized by non-biological processes in the laboratory have resulted exclusively in racemic mixtures. Unfortunately, most amino acids that have been extracted from meteorites are partially racemic, thus complicating an assessment of their modes of origin. Alternative pathways for the occurrence of partially racemized amino acids in biotic and abiotic materials are discussed in an attempt to clarify the significance of their occurrence in meteorites, in particular with respect to the origin of life in the solar system.