A comparison between immobilized pyrimidine nucleoside phosphorylase from Bacillus subtilis and thymidine phosphorylase from Escherichia coli in the synthesis of 5-substituted pyrimidine 2′-deoxyribonucleosides

- Immobilized PyNP from B. subtilis and TP from E. coli catalyze the synthesis of 5-halogenated pyrimidine 2′-deoxynucleosides.
- Differences between the enzymes cannot be seen in substrate specificity but in bioconversion rate.
- The synthesis of floxuridine is catalyzed up to 73-76% conversion in fully aqueous medium, pH 7.5 and room temperature.
- Immobilized enzymes are very stable in MeCN and DMF.
- Both biocatalysts appear to be promising in the large scale synthesis of base-modified pyrimidine nucleosides.