Encodes a 3'-phosphoadenosine-5'-phosphate (PAP) phosphatase that is sensitive to physiological concentrations of Na+. It does not also act as inositol polyphosphate 1-phosphatases, which other members of the HAL2-like family do. It is proposed that AHL acts in concert with sulphotransferases to prevent both the toxicity of PAP on RNA processing enzymes as well as the product inhibition of PAP on sulphate conjugation. The mRNA is cell-to-cell mobile.
Phosphatase that converts adenosine 3'-phosphate 5'-phosphosulfate (PAPS) to adenosine 5'-phosphosulfate (APS) and 3'-phosphoadenosine 5'-phosphate (3'-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.