title: Radiolysis, racemization and the origin of molecular asymmetry in the biosphere.
abstract: An investigation has been undertaken to determine whether ionizing radiation might engender racemization of optically active amino acids, along with their usual radiolysis. As prototypes, crystalline D- and L-leucine, as well as aqueous solutions of their sodium salts were exposed to the radiation from a 3000 Ci 60Co gamma-ray source. Gamma-ray doses which caused about 68% radiolysis of solid leucine left a residue which was about 5% racemized, while racemization proved even greater at lower doses for the dissolved sodium salts. In aqueous solution both percent degradation and percent racemization of the sodium salts were proportional to gamma-ray dosage within the range employed (1--27 x 10(6) rads). Implications of these observations for the origin of molecular asymmetry by the beta-decay parity violation mechanism are discussed.
mesh_terms: D005720:Gamma Rays; D007536:Isomerism; D007930:Leucine / Q000528:radiation effects*; D009904:Optical Rotation; D011854:Radiochemistry; D012995:Solubility
chemical_list: D007930:Leucine