Stereoselectivity of beta 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 interactions3,4 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 properties5,6. 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 experiments7–9—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 crust4,10,11. Experiments which aimed to generate optical activity in this manner are summarised in Table 1.