Contents

3'-Phosphoadenosine-5'-phosphosulfate

"PAPS" redirects here. For other uses, see Paps (disambiguation).

3′-Phosphoadenosine-5′-phosphosulfate

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
CAS Number	482-67-7 Y
3D model (JSmol)	Interactive image
Abbreviations	PAPS
ChEBI	CHEBI:17980 Y
ChemSpider	9799 Y
ECHA InfoCard	100.222.927
EC Number	694-699-5
IUPHAR/BPS	1719
KEGG	C00053
PubChem CID	10214
UNII	5TH3ERG159 Y
CompTox Dashboard (EPA)	DTXSID40894869
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 C1=NC2=C(C(=N1)N)N=CN2[C@H]3[C@@H]([C@@H]([C@H](O3)COP(=O)(O)OS(=O)(=O)O)OP(=O)(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). N verify (what is YN ?) Infobox references

3′-Phosphoadenosine-5′-phosphosulfate (PAPS) is a derivative of adenosine monophosphate (AMP) that is phosphorylated at the 3′ position and has a sulfate group attached to the 5′ phosphate. It is the most common coenzymeinsulfotransferase reactions and hence part of sulfation 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 and PAPSS2) using ATP as the phosphate donor.^[3][4]

Formation and reduction[edit]

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 sulfurylase:

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.^[5]

References[edit]