3'-Phosphoadenosine 5'-Phosphosulfate Synthase 1 (PAPSS1)

Three-prime-phosphoadenosine 5-prime-phosphosulfate (PAPS) is the sulfate donor cosubstrate for all sulfotransferase (SULT) enzymes. SULTs catalyze the sulfate conjugation of many endogenous and exogenous compounds, including drugs and other xenobiotics. In humans, PAPS is synthesized from adenosine 5-prime triphosphate (ATP) and inorganic sulfate by 2 isoforms, PAPSS1 and PAPSS2.

The predicted 623-amino acid protein is 98% identical to mouse PAPS synthase. The N-terminal 268-amino acid region of human PAPS synthase resembles APS kinases from other organisms and contains 3 conserved nucleotide-binding motifs. The 404-amino acid C-terminal domain shares approximately 57% identity with plant ATP sulfurylase.