光学活性起源的研究——Ⅵ.电子顺磁共振研究~(90)Sr-~(90)Yβ辐照D-和L-丙氨酸不对称自由基形成

STUDY ON THE SOURCE OF OPTICAL ACTIVITY Ⅵ. ESR SPECTROSCOPY ON THE ASYMMETRICAL RADICAL YIELDS IN ~(90)Sr-~(90)Y β IRRADIATED D- AND L- ALANINE

摘要: 利用电子顺磁共振(ESR)测量技术,研究~(90)Sr-~(90)Y的β粒子辐照D-和L-丙氨酸,产生自由基的不对称作用。实验结果表明,β粒子(左旋电子)优先引起D-丙氨酸的不对称分解。实验在77K下照射,然后在室温下立即用ESR谱测量。该实验说明基本粒子的手征不对称性,通过电弱作用力对氨基酸对映体立体有择辐解,在原初状态(Primary Stage)可被检测到。

Abstract: Free radical formation in 90Sr-90Y β irradiated D- and L- alanine is studied by ESR spectroscopy. To calibrate the probable differences in the size of ESR tubes,the different densities of alanine and the incidental different impurities, samples are firstly irradiated with 60Co γ rays. Then the D- and L- alanine samples are irradiated with 90Sr-90Y source at 77K. Soon after irradiation, ESR measurement is performed on each sample. The average ratio Hβ+γ/Hγ of D- alanine is 0. 147 higher than that of L- alanine , indicating that more free radicals are induced in D- alanine by β irradiation.Irradiation at 77K is capable of diminishing the effect of thermal movement on the polarization of β electrons and freezing the free radical formation. The experiments show the stereoselective interaction of β electrons with D- and L- amino acids,and so supports the Vester-ulbricht hypothesis.