Attachment of substrate metabolite to prostaglandin H synthase upon reaction with arachidonic acid.
Prostaglandin H synthase was incubated with [14C]arachidonate and then analyzed by polyacrylamide gel electrophoresis under denaturing conditions and by high pressure liquid chromatography. A maximum of 1 mol of arachidonate metabolite was found to become attached per mol of synthase subunit in a time-dependent process that was much slower than the rate of self-catalyzed inactivation of the cyclooxygenase activity. Incubation of a mixture of the synthase and ovalbumin with [14C]arachidonate resulted in a selective attachment of radiolabel to the synthase. These results suggest the presence of a single site on the synthase that is susceptible to reaction with an arachidonate metabolite.
D000818:Animals; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000378:metabolism*; D002250:Carbon Radioisotopes; D002851:Chromatography, High Pressure Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D007700:Kinetics; D008297:Male; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism*; D011485:Protein Binding; D012669:Seminal Vesicles / Q000201:enzymology; D012756:Sheep
D001095:Arachidonic Acids; D002250:Carbon Radioisotopes; D016718:Arachidonic Acid; D011451:Prostaglandin-Endoperoxide Synthases