Stereoselectivity of β irradiation of D,L-tryptophan in aqueous solution

Abstract

A POSSIBLE connection between the molecular asymmetry of living matter and the intrinsic asymmetry of elementary particles¹ was first suggested by Vester². All the experiments based essentially on the non-conservation of parity in weak interactions^3,4 can be classified as follows: (1) It is assumed that L- and D-enantiomers are not exact mirror images of each other but differ in their scalar physicochemical properties^5,6. Parity-violating forces originated by weak interactions could in principle give rise to different bond strengths in enantiomer molecules. If the recently discovered neutral weak currents turn out to be of vector and axialvector type—an opinion favoured by present neutrino experiments^7–9—there is necessarily an interference between parity-conserving electromagnetic interaction and parity-violating weak interaction; it might, however, be very small²³. The question whether a particular molecular quantum state does allow for the actual occurrence of a seizable parity-violating effect has, to our knowledge, not yet been settled. (2) It is supposed that the almost exclusive existence of one enantiomer in the biosphere is due to the asymmetric interaction of longitudinally polarised β rays with molecules (interaction either with racemic mixtures or with molecules undergoing reaction to form asymmetric compounds) during the early history of the earth. With this view it is believed that an induced optical activity is a result of the natural radiation from isotopes in the earth's crust^4,10,11. Experiments which aimed to generate optical activity in this manner are summarised in Table 1.