Prostaglandin-endoperoxide synthase | |||||||||
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Identifiers | |||||||||
EC no. | 1.14.99.1 | ||||||||
CAS no. | 9055-65-6 | ||||||||
Databases | |||||||||
IntEnz | IntEnz view | ||||||||
BRENDA | BRENDA entry | ||||||||
ExPASy | NiceZyme view | ||||||||
KEGG | KEGG entry | ||||||||
MetaCyc | metabolic pathway | ||||||||
PRIAM | profile | ||||||||
PDB structures | RCSB PDB PDBe PDBsum | ||||||||
Gene Ontology | AmiGO / QuickGO | ||||||||
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Cyclooxygenase 1 | |||||||
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![]() Crystallographic structure of prostaglandin H2 synthase-1 complex with flurbiprofen[1] | |||||||
Identifiers | |||||||
Symbol | PTGS1 | ||||||
Alt. symbols | COX-1 | ||||||
NCBI gene | 5742 | ||||||
HGNC | 9604 | ||||||
OMIM | 176805 | ||||||
PDB | 1CQE | ||||||
RefSeq | NM_080591 | ||||||
UniProt | P23219 | ||||||
Other data | |||||||
EC number | 1.14.99.1 | ||||||
Locus | Chr. 9 q32-q33.3 | ||||||
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Cyclooxygenase 2 | |||||||
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![]() Cyclooxygenase-2 (prostaglandin synthase-2) in complex with a COX-2 selective inhibitor[2] | |||||||
Identifiers | |||||||
Symbol | PTGS2 | ||||||
Alt. symbols | COX-2 | ||||||
NCBI gene | 5743 | ||||||
HGNC | 9605 | ||||||
OMIM | 600262 | ||||||
PDB | 6COX | ||||||
RefSeq | NM_000963 | ||||||
UniProt | P35354 | ||||||
Other data | |||||||
EC number | 1.14.99.1 | ||||||
Locus | Chr. 1 q25.2-25.3 | ||||||
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Cyclooxygenase (COX), officially known as prostaglandin-endoperoxide synthase (PTGS), is an enzyme (specifically, a family of isozymes, EC 1.14.99.1) that is responsible for biosynthesis of prostanoids, including thromboxane and prostaglandins such as prostacyclin, from arachidonic acid. A member of the animal-type heme peroxidase family, it is also known as prostaglandin G/H synthase. The specific reaction catalyzed is the conversion from arachidonic acid to prostaglandin H2 via a short-living prostaglandin G2 intermediate.[3][4]
Pharmaceutical inhibition of COX can provide relief from the symptoms of inflammation and pain.[3] Nonsteroidal anti-inflammatory drugs (NSAIDs), such as aspirin and ibuprofen, exert their effects through inhibition of COX. Those that are specific to the COX-2 isozyme are called COX-2 inhibitors. The active metabolite (AM404) of paracetamol is a COX inhibitor, a fact to which some or all of its therapeutic effect has been attributed.[5]
In medicine, the root symbol "COX" is encountered more often than "PTGS". In genetics, "PTGS" is officially used for this family of genes and proteins because the root symbol "COX" was already used for the cytochrome c oxidase family. Thus, the two isozymes found in humans, PTGS1 and PTGS2, are frequently called COX-1 and COX-2 in medical literature. The names "prostaglandin synthase (PHS)", "prostaglandin synthetase (PHS)", and "prostaglandin-endoperoxide synthetase (PES)" are older terms still sometimes used to refer to COX.
Arachidonic acid is a component of membrane phospholipids released either in a one-step process, after phospholipase A2 (PLA2) action, or a two-step process, after phospholipase C and DAG lipase actions. Arachidonic acid is then metabolized by cyclooxygenase (COX) and 5-lipoxygenase, resulting in the synthesis of prostaglandins and leukotrienes, respectively. These intracellular messengers play an important role in the regulation of signal transduction implicated in pain and inflammatory responses.