title: Biosynthesis of prostaglandins.
abstract: The generation of prostaglandins is catalyzed by a membrane-bound multienzyme complex. The first reaction of the biosynthetic sequence is the generation (by the enzyme 'fatty acid cyclooxygenase') of prostaglandin endoperoxides, a reaction which involves the incorporation of two moles of oxygen: this reaction probably proceeds by an ene reaction rather than a free-radical mechanism. After biosynthesis the endoperoxides can be metabolized in various ways depending on the cell-type. For example, in platelets they may be transformed into non-prostanoid compounds called thromboxanes, whereas vascular endothelium and many other tissues generate another derivative, prostacyclin. In other tissues, the 'classical' prostaglandins E, F or D may be generated. Some products of the cyclooxygenase (e.g. hydroperoxides, malonaldehyde) may have a direct toxic action on cells: prostaglandins themselves do not, but some types (especially those of the E series) are probably responsible for many of the clinical signs and symptoms of inflammation.
mesh_terms: D016861:Cyclooxygenase Inhibitors; D011464:Epoprostenol / Q000096:biosynthesis; D005227:Fatty Acids / Q000378:metabolism; D006880:Hydroxy Acids / Q000378:metabolism; D007249:Inflammation / Q000503:physiopathology; D050356:Lipid Metabolism; D011449:Prostaglandin Endoperoxides / Q000378:metabolism; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism; D011453:Prostaglandins / Q000096:biosynthesis*; D013379:Substrate Specificity; D009626:Terminology as Topic; D013931:Thromboxanes / Q000096:biosynthesis*
chemical_list: D016861:Cyclooxygenase Inhibitors; D005227:Fatty Acids; D006880:Hydroxy Acids; D011449:Prostaglandin Endoperoxides; D011453:Prostaglandins; D013931:Thromboxanes; D011464:Epoprostenol; D011451:Prostaglandin-Endoperoxide Synthases