The function of PAPSS2 (3'-phosphoadenosine 5'-phosphosulfate synthase 2, Ensembl gene identifier ENSG00000198682) is as follows. 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). {ECO:0000269|PubMed:11773860, ECO:0000269|PubMed:19474428, ECO:0000269|PubMed:23824674, ECO:0000269|PubMed:25594860, ECO:0000269|PubMed:9771708}.