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. 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. 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. PGH2 is unstable at room temperature, with a half life of 90-100 seconds, so it is often converted into a different prostaglandin.
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Other names
PGH2, Endoperoxide H2, Prostaglandin R2 | |
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ChEBI | |
ChemSpider | |
MeSH | Prostaglandin+H2 |
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CompTox Dashboard (EPA) |
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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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It is acted upon by:
- Prostacyclin synthase to create prostacyclin
- Thromboxane-A synthase to create thromboxane A2 and 12-(S)-hydroxy-5Z,8E,10E-heptadecatrienoic acid (HHT) (see 12-Hydroxyheptadecatrienoic acid)
- Prostaglandin D2 synthase to create prostaglandin D2
- Prostaglandin E synthase to create prostaglandin E2
It rearranges non-enzymatically to:
- A mixture of 12-(S)-hydroxy-5Z,8E,10E-heptadecatrienoic acid (HHT) and 12-(S)-hydroxy-5Z,8Z,10E-heptadecatrienoic acid (see 12-Hydroxyheptadecatrienoic acid)
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.
Effects of Aspirin on prostaglandin H2:
- Aspirin has been hypothesized to block the conversion of arachidonic acid to prostaglandin