Stimulation of prostaglandin biosynthesis by lipoic acid.
Enzyme preparations from sheep seminal vesicles display an enhanced ability to synthesize prostaglandins, particularly prostaglandin F from polyunsaturated fatty acids if alpha-lipoic acid is present in the incubation mixture prior to the addition of fatty acid. The stimulation by lipoate is reversible, time dependent, and involves modifications of V and Km for oxygenase activity. Product studies, structure vs. activity studies, and purification data indicate that lipoate exerts it effect by a mechanism distinct from a glutathione-like metabolism of the endoperoxide linkage in prostaglandin G and prostaglandin H. In addition, product studies suggest that lipoate is not a cofactor for the endoperoxide isomerase component of prostaglandin synthetase. Purification of the endoperoxide synthesizing activity by ion-exchange chromatography and isoelectric focusing yields preparations which are more responsive to lipoate than microsomal preparations.
D000818:Animals; D005978:Glutathione / Q000494:pharmacology; D007700:Kinetics; D008297:Male; D010101:Oxygen Consumption / Q000187:drug effects; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism; D011453:Prostaglandins / Q000096:biosynthesis*; D011458:Prostaglandins E / Q000096:biosynthesis; D011460:Prostaglandins F / Q000096:biosynthesis; D012669:Seminal Vesicles / Q000187:drug effects / Q000378:metabolism*; D013329:Structure-Activity Relationship; D008063:Thioctic Acid / Q000494:pharmacology*
D011453:Prostaglandins; D011458:Prostaglandins E; D011460:Prostaglandins F; D008063:Thioctic Acid; D011451:Prostaglandin-Endoperoxide Synthases; D005978:Glutathione