3'-Phosphoadenosine-5'-phosphosulfate

3'-Phosphoadenosine-5'-phosphosulfate

Names
IUPAC name 6-Amino-9-[(2R,3R,4S,5R)-3-hydroxy-5- [(hydroxy-sulfooxy-phosphoryl)oxymethyl] -4-phosphonooxy-tetrahydrofuran-2-yl]purine
Other names PAPS 3'-phosphoadenylyl sulfate phosphoadenosine phosphosulfate 3'-phospho-5'-adenylyl sulfate
Identifiers
CAS Number	482-67-7
3D model (Jmol)	Interactive image Interactive image
Abbreviations	PAPS
ChEBI	CHEBI:17980
ChemSpider	9799 Y
ECHA InfoCard	100.222.927
IUPHAR/BPS	1719
PubChem	10214
InChI InChI=1S/C10H15N5O13P2S/c11-8-5-9(13-2-12-8)15(3-14-5)10-6(16)7(27-29(17,18)19)4(26-10)1-25-30(20,21)28-31(22,23)24/h2-4,6-7,10,16H,1H2,(H,20,21)(H2,11,12,13)(H2,17,18,19)(H,22,23,24)/t4-,6-,7-,10-/m1/s1 Y Key: GACDQMDRPRGCTN-KQYNXXCUSA-N Y InChI=1/C10H15N5O13P2S/c11-8-5-9(13-2-12-8)15(3-14-5)10-6(16)7(27-29(17,18)19)4(26-10)1-25-30(20,21)28-31(22,23)24/h2-4,6-7,10,16H,1H2,(H,20,21)(H2,11,12,13)(H2,17,18,19)(H,22,23,24)/t4-,6-,7-,10-/m1/s1 Key: GACDQMDRPRGCTN-KQYNXXCUBK
SMILES S=C1=NC2=C(C(=N1)N)N=CN2C3C(C(C(O3)COP(=O)(O)OS(=O)(=O)O)OP(=O)(O)O)O O=S(=O)(O)OP(=O)(O)OC[C@H]3O[C@@H](n2cnc1c(ncnc12)N)[C@H](O)[C@@H]3OP(=O)(O)O
Properties
Chemical formula	C10H15N5O13P2S
Molar mass	507.266
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

3'-Phosphoadenosine-5'-phosphosulfate (PAPS) is a derivative of adenosine monophosphate that is phosphorylated at the 3' position and has a sulfate group attached to the 5' phosphate. It is the most common coenzyme in sulfotransferase reactions. It is endogenously synthesized by organisms via the phosphorylation of adenosine 5'-phosphosulfate (APS), an intermediary metabolite.^[1] In humans such reaction is performed by bifunctional 3'-phosphoadenosine 5'-phosphosulfate synthases (PAPSS1 and PAPSS2) using ATP as the phosphate donor.^[2]

Formation and reduction

APS and PAPS are intermediates in the reduction of sulfate to sulfite, an exothermic conversion that is carried out by sulfate-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 by ATP sulfurase:

SO₄²⁻ + ATP → APS + PP_i

The conversion of APS to PAPS is catalysed by APS kinase:

APS + ATP → PAPS + ADP

Reduction of APS leads to sulfite, which is further reduced to hydrogen sulfide, which is excreted. This process is called dissimilatory sulfate reduction. Reduction of PAPS, a more elaborated sulfate ester, leads also to hydrogen sulfide. But in this case, the product is used in biosynthesis, e.g. for the production of cysteine. The latter process is called assimilatory sulfate reduction because the sulfate sulfur is assimilated.^[3]

References