Bifunctional enzyme with both ATP sulfurylase and APS kinase activity, which mediates two steps in the sulfate activation pathway. The first step is the transfer of a sulfate group to ATP to yield adenosine 5′-phosphosulfate (APS), and the second step is the transfer of a phosphate group from ATP to APS yielding 3′-phosphoadenylylsulfate/PAPS, the activated sulfate donor used by sulfotransferases (PubMed:11773860, PubMed:19474428, PubMed:23824674, PubMed:25594860). In mammals, PAPS is the sole source of sulfate while APS appears to only be an intermediate in the sulfate-activation pathway (PubMed:11773860, PubMed:19474428, PubMed:23824674, PubMed:25594860). Plays indirectly an important role in skeletogenesis during postnatal growth (PubMed:9771708).
