Binds 1 zinc ion per subunit. Belongs to the metallo-dependent hydrolases superfamily. Adenosine and AMP deaminases family. Adenine deaminase type 2 subfamily. Although clearly a member of the adenine deaminase type 2 family, it lacks the conserved Glu active site residue in position 212 characteristic for this family. Its exact enzymatic activity is therefore unsure.