PGH2, prostaglandin endoperoxide

In the next step the —OOH group of PGG2 is reduced to an alcohol function Again prostaglandin endoperoxide synthase is the enzyme responsible The product of this step IS called PGH2... 

Prostaglandin Endoperoxides. The naturally occurring endoperoxides, PGG, PGG2, PGH, and PGH2, as well as a number of their... 

Synthesis of Several Analogs of the Prostaglandin Endoperoxide PGH2... 

Synthesis of prostaglandins and thromboxanes begins with the oxidative cyclization of free arachidonic acid to yield PGH2 by prostaglandin endoperoxide synthase—a microsomal protein that has two catalytic activities fatty acid cyclooxygenase (COX) and peroxidase. There are two isozymes of the synthase COX-1 and COX-2. Leukotrienes are produced by the 5-lipoxygenase pathway. 

Fig. (6). Vasoconstrictor mechanism of myricetin. PLA2 phospholipase A2 PL phospholipids AA arachidonic acid COX cyclooxygenase PGG2 prostaglandin G2 PGES prostaglandin endoperoxide synthase PGH2 prostaglandin Hi TXS Thromboxane synthase TXA2 Thromboxane A2 Tp Thromboxane receptor PKC protein kinase C.

Prostaglandins are biosynthesized from arachidonic acid, an unsaturated fatty acid containing four double bonds. The enzyme prostaglandin endoperoxide synthase converts arachidonic acid to PGH2, which serves as the precursor for prostaglandins and related compounds. Aspirin exerts its pharmacological effect by inhibiting this enzyme. 

Salomon, R.G., Miller, D.B., Zagorski, M.G., and Coughlin, D.J. Solvent Induced Fragmentation of Prostaglandin Endoperoxides. New Aldehyde Products from PGH2 and Novel Intramolecular 1,2-Hydride Shift During Endoperoxide Fragmentation in Aqueous Solution. J Am Chem Soc 106 (1984) 6049-6060. 

---