Prostaglandin H2

Prostaglandin H2 is a type of prostaglandin and a precursor for many other biologically significant molecules. It is synthesized from arachidonic acid in a reaction catalyzed by a cyclooxygenase enzyme.[2] The conversion from Arachidonic acid to Prostaglandin H2 is a two step process. First, COX-1 catalyzes the addition of two free oxygens to form the 1,2-Dioxane bridge and a peroxide functional group to form Prostaglandin G2.[3] Second, COX-2 reduces the peroxide functional group to a Secondary alcohol, forming Prostaglandin H2. Other peroxidases like Hydroquinone have been observed to reduce PGG2 to PGH2.[4] PGH2 is unstable at room temperature, with a half life of 90-100 seconds,[5] so it is often converted into a different prostaglandin.

Prostaglandin H2[1]
Prostaglandin H2 skeletal.svg
Names
Other names
PGH2, Endoperoxide H2, Prostaglandin R2
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
MeSH Prostaglandin+H2
UNII
Properties
C20H32O5
Molar mass 352.465 g/mol
Density 1.129 ± 0.06 g/mL
Boiling point 490 ± 40.0 °C
0.034 g/L
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
Eicosanoid synthesis - prostaglandin H2 near center

It is acted upon by:

It rearranges non-enzymatically to:

Use of prostaglandin H2:

  • regulating the constriction and dilation of blood vessels
  • stimulating platelet aggregation
    • binds to Thromboxane receptor on platelets' cell membranes to trigger platelet migration and adhesion to other platelets.[6]

Effects of Aspirin on prostaglandin H2:

  • Aspirin has been hypothesized to block the conversion of arachidonic acid to prostaglandin
Figure 1: Synthetic pathways from PGH2 (the parent compound) to prostaglandins, prostacyclin and thromboxanes

ReferencesEdit

  1. ^ "Prostaglandin H2". HMDB. Retrieved 19 November 2019.
  2. ^ van der Donk WA, Tsai AL, Kulmacz RJ (December 2002). "The cyclooxygenase reaction mechanism". Biochemistry. 41 (52): 15451–8. doi:10.1021/bi026938h. PMID 12501173.
  3. ^ Salomon RG, Miller DB, Zagorski MG, Coughlin DJ (October 1984). "Prostaglandin endoperoxides. 14. Solvent-induced fragmentation of prostaglandin endoperoxides. New aldehyde products from PGH2 and a novel intramolecular 1,2-hydride shift during endoperoxide fragmentation in aqueous solution". Journal of the American Chemical Society. 106 (20): 6049–6060. doi:10.1021/ja00332a049. ISSN 0002-7863.
  4. ^ Hla T, Neilson K (August 1992). "Human cyclooxygenase-2 cDNA". Proceedings of the National Academy of Sciences of the United States of America. 89 (16): 7384–8. Bibcode:1992PNAS...89.7384H. doi:10.1073/pnas.89.16.7384. PMC 49714. PMID 1380156.
  5. ^ "Human Metabolome Database: Showing metabocard for Prostaglandin H2 (HMDB0001381)". www.hmdb.ca. Retrieved 2019-11-19.
  6. ^ Woodward DF, Jones RL, Narumiya S (September 2011). "International Union of Basic and Clinical Pharmacology. LXXXIII: classification of prostanoid receptors, updating 15 years of progress". Pharmacological Reviews. 63 (3): 471–538. doi:10.1124/pr.110.003517. PMID 21752876.