Experience with the particulate prostaglandin endoperoxide synthase assay for testing non-steroidal antiinflammatory drugs.
A microsomal prostaglandin endoperoxide synthase preparation was obtained from sheep vesicular glands and used as a test system for non-steroidal antiinflammatory drugs. The activity was measured oxygraphically with arachidonic acid as substrate. The assay conditions were optimized with respect to the concentrations of enzyme, substrate and hydroperoxidase co-substrate as well as preincubation. The validity of the test was assessed by eight known prostaglandin H synthase inhibitors and two antiinflammatory drugs not acting on this enzyme. Sodium diclofenac proved to be the most potent inhibitor. As shown with indometacin as example the test shows a good reproducibility. The data were fitted to a kinetic mathematical model assuming two distinct inhibitor binding sites with different affinities. This model gave in most cases a good fitting of the experimental data.
Schewe
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C
Institute of Biochemistry, Medical School Charité, Humboldt-University, Berlin.
Ludwig
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P
Holzhütter
H G
HG
Schewe
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T
D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology*; D016718:Arachidonic Acid / Q000378:metabolism; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology*; D005088:Exocrine Glands / Q000201:enzymology; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D008861:Microsomes / Q000201:enzymology; D008954:Models, Biological; D011451:Prostaglandin-Endoperoxide Synthases / Q000032:analysis*; D012756:Sheep / Q000378:metabolism*
D000894:Anti-Inflammatory Agents, Non-Steroidal; D016861:Cyclooxygenase Inhibitors; D016718:Arachidonic Acid; D011451:Prostaglandin-Endoperoxide Synthases