Nucleotide analogs are mainly synthesized chemically. In contrast to the chemical synthesis routes, biocatalytic approaches offer several advantages: reactions can be performed at milder conditions, the use of harsh solvents is reduced, and the use of protection groups can be avoided due to a high regio-and stereoselectivity . For the biocatalytic nucleotide synthesis, enzymes of the de novo and salvage nucleotide pathway of various organisms were studied. These include, among others, phosphoribosyltransferases, nucleoside kinases (NKs), nucleoside monophosphate kinases (NMPKs) and nucleoside diphosphate kinases (NDPKs). We recently developed a general approach for the one-pot synthesis of nucleoside triphosphates from nucleosides using nucleoside and nucleotide kinases . By coupling the phosphorylation reactions with an adenosine-triphosphate (ATP)-regeneration system yields were significantly improved . Lately, cladribine triphosphate, a drug against leukemia and multiple sclerosis, was synthesized from 2-chloroadenine and phosphoribosyl pyrophosphate by an adenine phosphoribosyltransferase, polyphosphate kinase and ribonucleotide reductase . In this cascade reaction, polyphosphates served as a low-cost phosphate donor.