Adenosine 5'-phosphosulfate sodium salt is a sulfate ester of adenosine-5'-O-monophosphate (5'-AMP) and represents an active form of sulfate. Adenosine 5'-phosphosulfate is the substrate of the enzyme adenosine 5'-phosphosulfate reductase where sulfate uptaken from the environment and borne on Adenosine 5'-phosphosulfate is reduced to sulfite, and upon further transformation becomes available sulfur for subsequent biosynthetic reactions. A doubly phosphorylated analog, 3'-phosphoadenosine-5'-phosphosulfate (PAPS) is ubiquitous and a [35S]PAPS has been described as a photoaffinity ligand for sulfotransferase enzymes.
