Enzymatic formation of potential anticancer and antiviral inosine analogues.

Theoretically, inosine analogues should act as effective inhibitors of tumor cell proliferation and viral replication. To acquire a broad spectrum of new candidate inosine analogues, a rapid, facile, quantitative and stereoselective method for deaminating potential antitumor and antiviral adenine analogues previously synthesized in our laboratory was developed. A novel 5'-adenylic acid deaminase, with relaxed substrate requirements, from Aspergillus species was utilized to deaminate four hexofuranosyladenine nucleosides and five adenine nucleoside dialdehydes to their corresponding inosine analogues. The fastest rates of deamination for the hexofuranosyl nucleosides were for the compounds where the vicinal hydroxyl groups on the sugars are oriented in the erythro configuration. For rapid deamination of the adenine nucleoside dialdehydes, the R configuration at the proximal carbon atom is preferred, while the nature of the group on the distal carbon atom has no significant effect on the rate or extent of deamination.