Biosynthesis of H-2-labeled inosine by the bacterium Bacillus subtilis in 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 ind ividual colonies an 2% agar with (H2O)-H-2 and subsequent selection. For gr owing the strain, a special heavy hydrogen medium with a high level of deut eration (89-90 at. % H-2) based on 2% hydrolyzate of the biomass of the met hylotrophic Brevibacterium methylicum as a source of H-2-labeled growth sub strates was obtained on 98 vol % (H2O)-H-2 and 2 vol % [U-H-2] 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 m ass-spectroscopy of fast atoms has shown a polymorphism of deuterium incorp oration in the molecule (isotope composition of inosine: 4 at. H-2, 20%; 5 at. H-2, 38%; 6 at. H-2, 28%; 7 at. H-2, 14%), deuterium being incorporated in the ribose and hypoxanthine fragments of the molecules.