TIGR00339

ATP sulphurylase; This enzyme forms adenosine 5'-phosphosulfate (APS) from ATP and free sulfate, the first step in the formation of the activated sulfate donor 3'-phosphoadenylylsulfate (PAPS). In some cases, it is found in a bifunctional protein in which the other domain, APS kinase, catalyzes the second and final step, the phosphorylation of APS to PAPS; the combined ATP sulfurylase/APS kinase may be called PAPS synthase. Members of this family also include the dissimilatory sulfate adenylyltransferase (sat) of the sulfate reducer Archaeoglobus fulgidus [Central intermediary metabolism, Sulfur metabolism].