title: Experiments on the abiotic amplification of optical activity.
abstract: Our earlier experiments are briefly reviewed, involving the abiotic generation of optical activity by exposure of DL-amino acids to various "chiral" physical forces. The enantiomeric enrichments so obtained were low, however, and additional experiments were undertaken with the objective of abiotically enhancing such small enantiomeric excesses. D not equal to L Mixtures of leucine N-carboxy anhydride gave enantiomerically enriched polymers on partial polymerization, while valine NCA mixtures behaved oppositely. Leucine polymers were also found to hydrolyze stereoselectively, providing for additional enantiomeric enhancement. A repetitive sequence of partial polymerization-hydrolysis steps is suggested as a possible mechanism for the abiotic genesis of optically enriched polypeptides on the primitive Earth.
mesh_terms: D000596:Amino Acids / Q000528:radiation effects; D006868:Hydrolysis; D007930:Leucine / Q000031:analogs & derivatives; D009904:Optical Rotation; D010455:Peptides; D011108:Polymers; D013237:Stereoisomerism; D014633:Valine / Q000031:analogs & derivatives
chemical_list: D000596:Amino Acids; D010455:Peptides; D011108:Polymers; C030047:leucine N-carboxy anhydride; C030046:N-carboxyvaline anhydride; C027819:polyleucine; D007930:Leucine; D014633:Valine