This domain is found in phosphoadenosine phosphosulphate (PAPS) reductaseenzymes or PAPS sulphotransferase. PAPS reductase is part of the adenine nucleotide alpha hydrolases superfamily also including N type ATP PPasesand ATP sulphurylases [<cite idref="PUB00005294"/>]. The enzyme uses thioredoxin as an electron donor for the reduction of PAPS to phospho-adenosine-phosphate (PAP) [<cite idref="PUB00005294"/>, <cite idref="PUB00001462"/>].It is also found in NodP nodulation protein P from <taxon tax_id="382">Rhizobium meliloti</taxon> (Sinorhizobium meliloti) which has ATPsulphurylase activity (sulphate adenylate transferase) [<cite idref="PUB00004086"/>]. Phosphoadenosine phosphosulphate reductase