Abstract: A method for producing cladribine (2-chloro-2? deoxyadenosine) comprising the steps of: a) reaction of 2-deoxyuridine with 2-chloroadenine, in the presence of uridine phosphorylase (UPase) and purine nucleoside phosphorylase (PNPase) in an aqueous reaction medium possibly containing up to 40% v/v of an aprotic dipolar solvent, to obtain cladribine dissolved in said reaction medium; b) isolation of the cladribine by precipitation by means of concentration and alkalinisation of the reaction medium up to pH 11.5-12.5.

Abstract: A method for producing cladribine (2-chloro-2?-deoxyadenosine) comprising the steps of: a) reaction of 2-deoxyuridine with 2-chloroadenine, in the presence of uridine phosphorylase (UPase) and purine nucleoside phosphorylase (PNPase) in an aqueous reaction medium possibly containing up to 40% v/v of an aprotic dipolar solvent, to obtain cladribine dissolved in said reaction medium; b) isolation of the cladribine by precipitation by means of concentration and alkalinisation of the reaction medium up to pH 11.5-12.5.

Abstract: Novel strains of genetically modified prokaryotic micro-organisms capable of expressing polypeptides having the enzyme activity of the enzymes uridine phosphorylase (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.

Abstract: A process for immobilizing cells is described, particularly procaryotic cells, which includes a step of adsorbing said cells on a resin, wherein such a resin is a weak anionic exchange resin and preferably has amino moieties; when the immobilized cells are UPase and/or PNPase producing cells, nucleosides can be produced by reaction of a pentose-1-phosphate with a purine or pyrimidine base, and transglycosylation reactions can be performed; advantageously, as immobilized UPase or PNPase producing cells, Escherichia cells of the DH5alpha strain transformed by the plasmid vectors having the sequences reported in Seq. Id. No. 1 and 2. are used.

Abstract: Novel strains of genetically modified prokaryotic micro-organisms capable of expressing polypeptides having the enzyme activity of the enzymes uridine phosphorylase (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.

Abstract: 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.

Abstract: The preparation of novel biocatalysts is described; the biocatalysts are produced by the co-immobilization of the recombinant enzymes uridine phosphorylase and purine nucleoside phosphorylase by means of covalent bonds on solid substrates functionalized with epoxy groups. The novel biocatalysts are usable for successive reaction cycles, are resistant to heat and to the presence of solvents, and can advantageously be used in the industrial production of natural nucleosides and of modified analogues of pharmaceutical interest.

Abstract: 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.