1. Actuality of the work proposed.
1.1. Deuterium (2H), the hydrogen isotope with mass 2, was discovered by Urey. In the years immediately following this discovery, there developed a keen interest in a biological enrichment of a cell with 2H, which resulted in a miscellany of rather confusing data (Katz J., Crespy H. L. 1972). The main conclusion that can be derived from the most competent and comprehensive of the early studies is that high concentrations of 2H2O are incompatible with life and reproduction. Nevertheless, a many cells could be quite well adapted to 2H2O, so that a discussion about the role of macromolecules in biolodical adaptation to 2H2O is still actual through more than four decades of years after the first description of the biological consequences of hydrogen replacement by deuterium.