Strains of genetically modified prokaryotic micro-organisms capable of expressing
polypeptides having the enzyme activity of the enzymes uridine posphorylase (UdP)
and purine nucleoside phosphorylase (PNP) are described; the strains in question
can be used, both in the form of whole cells and in the form of crude or purified
extracts, to catalyse transglycosylation reactions between a donor nucleoside and
an acceptor base with particularly high yields. The associated plasmid vectors
are also described.
