Biomaterial Database

Cooxidation of the clinical reagent 3,5,3'5'-tetramethylbenzidine by prostaglandin synthase. 1982

P D Josephy, and R P Mason, and T Eling

Prostaglandin synthase catalyzes the oxidation of arachidonic acid to prostaglandin H2 via a hydroperoxide intermediate, prostaglandin G2. The prostaglandin synthase system cooxidizes 3,5,3'5'-tetramethylbenzidine (TMB), a derivative of the human carcinogen benzidine, to colored products. This process is arachidonic acid dependent and indomethacin sensitive. The reaction is also supported by hydroperoxides, and, in this case, indomethacin has no effect. This suggests that the cooxidation is mediated by the hydroperoxidase activity of prostaglandin synthase. The products of TMB oxidation by this system are the same as those obtained with lactoperoxidase and H2O2 or with horseradish peroxidase and H202. The initial products of TMB oxidation are the TMB radical cation and a charge-transfer complex composed of TMB and its two-electron (diimine) oxidation product. The TMB radical cation was identified by electron spin resonance spectroscopy. Ascorbic acid reduces the products, regenerating the parent compound.

UI	MeSH Term	Description	Entries
D011451	Prostaglandin-Endoperoxide Synthases	Enzyme complexes that catalyze the formation of PROSTAGLANDINS from the appropriate unsaturated FATTY ACIDS, molecular OXYGEN, and a reduced acceptor.	Fatty Acid Cyclo-Oxygenase,PGH Synthase,Prostaglandin H Synthase,Prostaglandin Synthase,Prostaglandin-Endoperoxide Synthase,Arachidonic Acid Cyclooxygenase,Cyclo-Oxygenase,Cyclooxygenase,Cyclooxygenases,Hydroperoxide Cyclase,PGH2 Synthetase,Prostaglandin Cyclo-Oxygenase,Prostaglandin Cyclooxygenase,Prostaglandin Endoperoxide Synthetase,Prostaglandin G-H Synthase,Prostaglandin H2 Synthetase,Prostaglandin Synthetase,Cyclase, Hydroperoxide,Cyclo Oxygenase,Cyclo-Oxygenase, Fatty Acid,Cyclo-Oxygenase, Prostaglandin,Cyclooxygenase, Arachidonic Acid,Cyclooxygenase, Prostaglandin,Endoperoxide Synthetase, Prostaglandin,Fatty Acid Cyclo Oxygenase,G-H Synthase, Prostaglandin,Prostaglandin Cyclo Oxygenase,Prostaglandin Endoperoxide Synthases,Prostaglandin G H Synthase,Synthase, PGH,Synthase, Prostaglandin,Synthase, Prostaglandin G-H,Synthase, Prostaglandin H,Synthase, Prostaglandin-Endoperoxide,Synthases, Prostaglandin-Endoperoxide,Synthetase, PGH2,Synthetase, Prostaglandin,Synthetase, Prostaglandin Endoperoxide,Synthetase, Prostaglandin H2
D002621	Chemistry	A basic science concerned with the composition, structure, and properties of matter; and the reactions that occur between substances and the associated energy exchange.
D001560	Benzidines	Very toxic industrial chemicals. They are absorbed through the skin, causing lethal blood, bladder, liver, and kidney damage and are potent, broad-spectrum carcinogens in most species.	Bianilines,Biphenyldiamines
D055598	Chemical Phenomena	The composition, structure, conformation, and properties of atoms and molecules, and their reaction and interaction processes.	Chemical Concepts,Chemical Processes,Physical Chemistry Concepts,Physical Chemistry Processes,Physicochemical Concepts,Physicochemical Phenomena,Physicochemical Processes,Chemical Phenomenon,Chemical Process,Physical Chemistry Phenomena,Physical Chemistry Process,Physicochemical Phenomenon,Physicochemical Process,Chemical Concept,Chemistry Process, Physical,Chemistry Processes, Physical,Concept, Chemical,Concept, Physical Chemistry,Concept, Physicochemical,Concepts, Chemical,Concepts, Physical Chemistry,Concepts, Physicochemical,Phenomena, Chemical,Phenomena, Physical Chemistry,Phenomena, Physicochemical,Phenomenon, Chemical,Phenomenon, Physicochemical,Physical Chemistry Concept,Physicochemical Concept,Process, Chemical,Process, Physical Chemistry,Process, Physicochemical,Processes, Chemical,Processes, Physical Chemistry,Processes, Physicochemical