Thermophile bacterium Geobacillus kaustophilus was able to synthesize 5-fluoro-2´-deoxyuridine (floxuridine) to 52 mg.L‑1.h‑1 using whole cells. The presence of 1 mmol.L‑1 ZnCl2 enhanced transglycosylation reaction. The reaction was also enhanced when 2-deoxyuridine (2’dur) was, even partially, replaced with 5-fluoro-2´-deoxyriboside (5’Fdri). The highest production of floxuridine was observed at the 5’Fdri to 2’dur ratio of 5:1, i.e. when 5’Fdri was in great excess. G. kaustophilus can accept both 6-oxo- and 6‑aminopurine nucleotides as substrates, but oxo-nucleotides are more efficient substrates than 2´-amino modified compounds. Mass spectrometric analyses resulted in the identification of 23 proteins representing metabolic enzymes, and purine nucleotide phosphorylase DeoD subunit. This strain can be used as a catalyst in the biosynthesis of 2´‑fluorinate nucleotides.
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