Study on the source of optical activity: Pt. 4

On purpose to examine Vester-Ulbricht hypothesis, i.e., the origin of optical activity via parity nonconservation during the decay of certain radioactive isotopes. Since leucine has one of the larger g factor (the anisotropy factor) among the proteinaceous amino acids and Norden reported that the decarboxylation of sublimed solid D-and L-leucine by γ rays give quite different quantum yields, indicating significant stereo selection but this effect vanishes by crystallization instead of sublimation. The beta radiolysis of sublimed D,L-leucine with 90Sr-90Y is studied by using chirasil-val capillary column gas chromatography. The sublimed solid D,L-leucine was irradiated with 90Sr-90Y source for a total dose of 7.56 x 104 Gy. The decomposition rates for three D,L-leucine samples are found to be 12.8%, 14.2% and 12.5% and the corresponding G values are 125, 139 and 122 respectively. The large G values of D,L-leucine suggest a chain reaction. Within experimental error, the stereoselective radiolysis is not observed at thermodynamic equilibrium state. The further experiments are in progress