Prostaglandin-endoperoxide synthase 2

Prostaglandin-endoperoxide synthase 2 (prostaglandin G/H synthase and cyclooxygenase) (The HUGO official symbol is PTGS2; HGNC ID, HGNC:9605), also known as cyclooxygenase-2 or COX-2, is an enzyme that in humans is encoded by the PTGS2 gene. Because the "COX" term is used for the stem symbol for "cytochrome c oxidase" family of genes and gene products including proteins, the "PTGS" symbol is used for the prostaglandin-endoperoxide synthase (cyclooxygenase) family of genes and proteins. It is involved in the conversion of arachidonic acid to prostaglandin H2, an important precursor of prostacyclin and thromboxane A2, among others.

History

PTGS2 (COX-2) was discovered in 1991 by the Daniel Simmons laboratory at Brigham Young University.

Function

PTGS2 (COX-2), converts arachidonic acid (AA) to prostaglandin endoperoxide H2. PGHSs are targets for NSAIDs and PTGS2 (COX-2) specific inhibitors called coxibs. PGHS-2 is a sequence homodimer. Each monomer of the enzyme has a peroxidase and a PTGS (COX) active site. The PTGS (COX) enzymes catalyze the conversion of arachidonic acid to prostaglandins in a two steps. First, hydrogen is abstracted from carbon 13 of arachidonic acid, and then two molecules of oxygen are added by the PTGS2 (COX-2), giving PGG2. Second, PGG2 is reduced to PGH2 in the peroxidase active site. The synthesized PGH2 is converted to prostaglandins (PGD2, PGE2, PGF_2α), prostacyclin (PGI2), or thromboxane A2 by tissue-specific isomerases.(Figure 2)