Catalyzes the hydrolytic deamination of adenine to hypoxanthine. Plays an important role in the purine salvage pathway and in nitrogen catabolism. adenine + H(+) + H2O = hypoxanthine + NH4(+) Binds 1 zinc ion per subunit. Belongs to the metallo-dependent hydrolases superfamily. Adenosine and AMP deaminases family. Adenine deaminase type 2 subfamily. Truncated N-terminus.