Converts adenosine 3'-phosphate 5'-phosphosulfate (PAPS) to adenosine 5'-phosphosulfate (APS) and 3'(2')-phosphoadenosine 5'- phosphate (PAP) to AMP (PubMed:10205895). May regulate the flux of sulfur in the sulfur-activation pathway by converting PAPS to APS (By similarity). Prevents both the toxicity of PAP on RNA processing enzymes as well as the product inhibition by PAP of sulfate conjugation. adenosine 3',5'-bisphosphate + H2O = AMP + phosphate Inhibited by Li(+) (IC(50)=10 mM), Na(+) (IC(50)=50 mM) and Ca(2+) (IC(50)=0.06 mM). Expressed in roots, leaves, stems, flowers and siliques. Substrate preference is 3'-phosphoadenosine 5'-phosphate (PAP) = adenosine 3'-phosphate 5'-phosphosulfate (PAPS). No activity observed against 3' or 5'-AMP, inositol mono and diphosphates and fructose-1,6-bisphosphate. Belongs to the inositol monophosphatase superfamily.