Exhibits adenosine 5'-monophosphoramidase activity, hydrolyzing purine nucleotide phosphoramidates with a single phosphate group such as adenosine 5'monophosphoramidate (AMP-NH2) to yield AMP and NH2. Hydrolyzes adenosine 5'-O-p-nitrophenylphosphoramidate (AMP-pNA). May be involved in steroid biosynthesis. May play a role in apoptosis.