Large scale synthesis of dinucleoside monophosphates catalyzed by ribonuclease from Aspergillus clavatus

A gram scale enzymatic synthesis of eight, dinucleoside monophosphates (ApC, ApU, CpC, CpU, GpC, GpU, UpC, and UpU) is described. The synthesis involves a reaction between the appropriate ribonucleoside‐2′,3′‐cyclie phosphates and cytidine or uridine in the presence of ribonuelease from Aspergillus clavatus at 30°C. The enzyme is removed from the reaction mixture by chromatography on Bio‐Gel P–4, and the dinucleoside monophosphate is further purified by chromatography on a DEAE‐Sephadex A–25, column. A procedure for the large scale preparation of the ribonuclease from Aspergillus clavatus is also described.