3'-Phosphoadenosine-5'-phosphosulfate

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3'-Phosphoadenosine-5'-phosphosulfate
3'-Phosphoadenosine-5'-phosphosulfate.svg
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
482-67-7
Abbreviations PAPS
ChEBI CHEBI:17980
ChemSpider 9799 YesY
1719
Jmol 3D model Interactive image
Interactive image
PubChem 10214
Properties
C10H15N5O13P2S
Molar mass 507.266
Vapor pressure {{{value}}}
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
YesY verify (what is YesYN ?)
Infobox references

3'-Phosphoadenosine-5'-phosphosulfate is a derivative of adenosine monophosphate that is phosphorylated at the 3' position and has a sulfate group attached to the 5' phosphate. This anion, abbreviated PAPS, is the most common coenzyme in sulfotransferase reactions. A related anion is adenosine 5'-phosphosulfate (APS), which is not phosphorylated at the 3' position.[1]

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 + PPi

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.[2]

References

  1. Lua error in Module:Citation/CS1/Identifiers at line 47: attempt to index field 'wikibase' (a nil value).
  2. M. T. Madigan, J. M. Martinko, J. Parker “Brock Biology of Microorganisms” Prentice Hall, 1997. ISBN 0-13-520875-0.