[The biosynthesis of 2H-labelled inosine by Bacillus subtilis bacteria in a heavy-hydrogen medium]

We studied biosynthesis of the purine ribonucleoside inosine by the strain of Bacillus subtilis, which was adapted to deuterium through plating to individual colonies on 2% agar with 2H2O and subsequent selection. For growing the strain, a special heavy hydrogen medium with a high level of deuteration (89-90 at. % 2H) based on 2% hydrolyzate of the biomass of the methylotrophic Brevibacterium methylicum as a source of 2H-labeled growth substrates was obtained on 98 vol % 2H2O and 2 vol % [U-2H] methanol. We provide experimental data on the strain growth and accumulation of inosine in the culture medium. A study of the level of inosine deuteration using mass-spectroscopy of fast atoms has shown a polymorphism of deuterium incorporation in the molecule (isotope composition of inosine: 4 at. 2H, 20%; 5 at. 2H, 38%; 6 at. 2H, 28%; 7 at. 2H, 14%), deuterium being incorporated in the ribose and hypoxanthine fragments of the molecules.