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It has been found that human PTGS2 (COX-2) functions as a conformational heterodimer having a catalytic monomer (E-cat) and an allosteric monomer (E-allo). Heme binds only to the peroxidase site of E-cat while substrates, as well as certain inhibitors (e.g. celecoxib), bind the COX site of E-cat. E-cat is regulated by E-allo in a way dependent ...
COX-2 inhibitors have been found to be effective in suppressing inflammatory neurodegenerative pathways, with beneficial results in animal studies for major depressive disorder, as well as schizophrenia, bipolar disorder, and obsessive-compulsive disorder. [17] These need to be confirmed in human clinical trials. [18]
The impetus for development of selective COX-2 inhibitors was the adverse gastrointestinal side-effects of NSAIDs.Soon after the discovery of the mechanism of action of NSAIDs, strong indications emerged for alternative forms of COX, but little supporting evidence was found.
COX is a common target for anti-inflammatory drugs. The most significant difference between the isoenzymes, which allows for selective inhibition, is the substitution of isoleucine at position 523 in COX-1 with valine in COX-2. The smaller Val 523 residue in COX-2 allows access to a hydrophobic side-pocket in the enzyme (which Ile 523 ...
Prostaglandins are produced following the sequential oxygenation of arachidonic acid, DGLA or EPA by cyclooxygenases (COX-1 and COX-2) and terminal prostaglandin synthases. The classic dogma is as follows: COX-1 is responsible for the baseline levels of prostaglandins. COX-2 produces prostaglandins through stimulation.
Rofecoxib is a selective COX-2 inhibitor, or "coxib". Though the class of coxibs includes several agents, degrees of COX-2 selectivity vary among them, with celecoxib (Celebrex) being the least COX-2 selective, and rofecoxib (Vioxx), valdecoxib (Bextra), and etoricoxib (Arcoxia), being highly COX-2 selective. [10]
Newer NSAID drugs called COX-2 selective inhibitors have been developed that inhibit only COX-2, with the hope for reduction of gastrointestinal side-effects. [8] However, several COX-2 selective inhibitors have subsequently been withdrawn after evidence emerged that COX-2 inhibitors increase the risk of heart attack. [9]
In eukaryotes this enzyme complex is located in the mitochondrial inner membrane; in aerobic prokaryotes it is found in the plasma membrane. The enzyme complex consists of 3-4 subunits (prokaryotes) to up to 13 polypeptides (mammals). The N-terminal domain of cytochrome C oxidase contains two transmembrane alpha-helices.