InterPro domain: IPR006239

Sulphate is incorporated into 3-phosphoadenylylsulphate, PAPS, for utilization in pathways such as methionine biosynthesis. Transfer of sulphate from PAPS to an acceptor leaves adenosine 3'-5'-bisphosphate, APS. In plants these sequences represent a form of the enzyme, 3'(2'),5'-bisphosphate nucleotidase, which removes the 3'-phosphate from APS to regenerate AMP and help drive the cycle. Sensitivity of this essential enzyme to sodium and other metal ions results is responsible for characterisation of this enzyme as a salt tolerance protein [ 1 ]. Some members of this family are active also as inositol 1-monophosphatase.

1. The Arabidopsis HAL2-like gene family includes a novel sodium-sensitive phosphatase. Plant J. 17, 373-83