Adenylic acid deaminase from Aspergillus niger (AMP deaminase; AMPDA, EC 3.5. 4.6) has been introduced as a novel practical catalyst in the synthesis of 6-oxopurine riboside and their analogs. This enzyme has a very broad substrate specificity and has been used on a preparative scale for deamination of several derivatives of adenosine including phosphorylated, cyclic, carbocyclic as well as acyclic analogs. In addition, AMPDA ...