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 (By similarity). Hydrolyzes adenosine 5'-O-p-nitrophenylphosphoramidate (AMP-pNA) (By similarity). May be involved in steroid biosynthesis (By similarity). May play a role in apoptosis (By similarity). adenosine 5'-phosphoramidate + H2O = AMP + NH4(+) Belongs to the HINT family.