<p>This entry consists of sulphate adenylyltransferase or ATP-sulfurylase (<db_xref db="EC" dbkey="2.7.7.4"/>) some of which are part of a bifunctional polypeptide chain associated with adenosyl phosphosulphate (APS) kinase, <db_xref db="INTERPRO" dbkey="IPR002891"/>. Both enzymes are required for PAPS (phosphoadenosine-phosphosulphate) synthesis from inorganic sulphate [<cite idref="PUB00001859"/>]. ATP sulfurylase catalyses the synthesis of adenosine-phosphosulphate APS from ATP and inorganic sulphate [<cite idref="PUB00004924"/>].</p>