A novel enzymatic method for the production of purine-2′-deoxyribonucleosides

The microbial production of purine-2′-deoxyribonucleosides from pyrimidine-2′-deoxyribonucleosides and purine bases was examined by the application of nucleoside phosphorylase using Enterobacter aerogenes AJ-11125 as the enzyme source. In this system, 2′-deoxyadenosine (dAR) was efficiently produced from 2′-deoxyuridine (dUR) and adenine. In contrast, 2′-deoxyguanosine (dGR) was scarcely produced from dUR and guanine, because of the low solubility of guanine. Under the conditions using guanosine (GR) with higher solubility than guanine as a guanine source, higher productivity of dGR was obtained, but the maximal molar yield obtained was less than 20%. To improve its productivity, we newly constructed a following enzymatic method via 2,6-diaminopurine-2′-deoxyriboside (dDAPR) as follows: production of dDAPR from dUR and 2,6-diaminopurine (DAP) by E. aerogenes AJ-11125, followed by the conversion of dDAPR to dGR by adenosine deaminase. Through the successive reactions, dGR was efficiently produced with high yield.