Prostaglandin E synthase isomerizes PGH2 to PGE2 Authored: Jassal, B, 2008-10-01 13:18:42 EC Number: 5.3.99.3 Prostaglandin E2 (PGE2) is the most abundant prostanoid in the body and is a major mediator of inflammation in diseases such as osteoarthritis and rheumatoid arthritis. The product of arachidonic acid, prostaglandin H2 (PGH2) serves as the substrate for the isomerization to PGE2. The conversion is carried out by prostaglandin E synthase (PGES), of which there are three forms. Two are membrane-bound enzymes and are designated as mPGES-1 (functionally linked with COX-2) and mPGES-2 (golgi membrane-associated, functionally coupled with both COX-1 and COX-2). The other is cytosolic (cPGES, PTGES3) and functionally linked to COX-1 to produce PGE2 immediately. In this reaction, cPGES is used for conversion of PGH2 to PGE2. Pubmed10922363 Reactome Database ID Release 43265295 Reactome, http://www.reactome.org ReactomeREACT_15459 Reviewed: Rush, MG, 2012-11-10