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| Names | |
|---|---|
| IUPAC name 3′-O-Phosphono-5′-adenylyl hydrogen sulfate | |
| Systematic IUPAC name [(2R,3S,4R,5R)-5-(6-Amino-9H-purin-9-yl)-4-hydroxy-3-(phosphonooxy)oxolan-2-yl]methyl hydrogen (sulfooxy)phosphonate | |
| Other names PAPS 3′-Phosphoadenylyl sulfate Phosphoadenosine phosphosulfate 3′-Phospho-5′-adenylyl sulfate | |
| Identifiers | |
| |
3D model (JSmol) | |
| Abbreviations | PAPS |
| ChEBI | |
| ChemSpider |
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| ECHA InfoCard | 100.222.927 |
| EC Number |
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| KEGG | |
| UNII | |
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| Properties | |
| C10H15N5O13P2S | |
| Molar mass | 507.266 |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
3′-Phosphoadenosine-5′-phosphosulfate (PAPS) is a derivative ofadenosine monophosphate (AMP) that isphosphorylated at the 3′ position and has asulfate group attached to the 5′phosphate. It is the most commoncoenzyme insulfotransferase reactions and hence part ofsulfation pathways.[1] It is endogenously synthesized by organisms via the phosphorylation of adenosine 5′-phosphosulfate (APS), an intermediary metabolite.[2] In humans such reaction is performed by bifunctional 3′-phosphoadenosine 5′-phosphosulfate synthases (PAPSS1 andPAPSS2) usingATP as the phosphate donor.[3][4]
APS and PAPS are intermediates in the reduction of sulfate tosulfite, an exothermic conversion that is carried out bysulfate-reducing bacteria. In these organisms, sulfate serves as an electron acceptor, akin to the use of O2 as an electron acceptor by aerobic organisms. Sulfate is not reduced directly but must be activated by the formation of APS or PAPS. These carriers of activated sulfate are produced by reaction with ATP. The first reaction is catalysed byATP sulfurylase:
The conversion of APS to PAPS is catalysed byAPS kinase:
Reduction of APS leads to sulfite, which is further reduced tohydrogen sulfide, which is excreted. This process is called dissimilatory sulfate reduction. Reduction of PAPS, a more elaboratedsulfate ester, leads also to hydrogen sulfide. But in this case, the product is used in biosynthesis, e.g. for the production ofcysteine. The latter process is called assimilatory sulfate reduction because the sulfate sulfur is assimilated.[5]
