Verification of the plastic isotope effects in living cells

D/H conversion in glutamine and asparagine originally crystallized in H2O when placed in D2O medium was studied by theoretically and experimentally. Based on density functional theory (DFT) developed by Kohn-Sham, change in IR absorption spectrum by D/H conversion was calculated. The results indicate that the mass change due to D/H conversion induces not only frequency change but also mode change of molecular vibration. Raman scattering and Fourier transformed IR-ATR absorption spectrum of deuterated amino acids were obtained and their variation with passage of time when maintained in H2O was recorded. Moreover, nerve cells of a mouse (tublin) in D2O and H2O were observed with electron microscopy. These results all are consistent with the two working hypothesis: (1) The H-D conversion in living cells is principally due to change in quantum fluctuation (zero point energy), and (2) A process of structural change is slowed down while replacing H by D. (S. Ohno)