Synthesis of prostaglandin F ethanolamide by prostaglandin F synthase and identification of Bimatoprost as a potent inhibitor of the enzyme: new enzyme assay method using LC/ESI/MS.
Prostaglandin (PG) D(2) ethanolamide (prostamide D(2)) was reduced to 9alpha,11beta-PGF(2) ethanolamide (9alpha,11beta-prostamide F(2)) by PGF synthase, which also catalyzes the reduction of PGH(2) and PGD(2) to PGF(2alpha) and 9alpha,11beta-PGF(2), respectively. These enzyme activities were measured by a new method, the liquid chromatographic-electrospray ionization-mass spectrometry (LC/ESI/MS) technique, which could simultaneously detect the substrate and all products. PGF(2alpha), 9alpha,11beta-PGF(2), PGD(2), PGH(2), 9alpha,11beta-prostamide F(2), and prostamide D(2) were separated on a TSKgel ODS 80Ts column, ionized by electrospray, and detected in the negative mode. Selected ion monitoring (SIM) of m/z 353 ([M-H](-)), 353 ([M-H](-)), 351 ([M-H](-)), 333 ([M-H-H(2)O](-)), 456 ([M+59](-)), and m/z 358 ([M-37](-)) was used for quantifying PGF(2alpha), 9alpha,11beta-PGF(2), PGD(2), PGH(2), 9alpha,11beta-prostamide F(2), and prostamide D(2), respectively. The detection limit for PGF(2alpha) and 9alpha,11beta-PGF(2) was 0.01pmol; that for PGH(2) and PGD(2), 0.1pmol; and that for prostamide D(2) and 9alpha,11beta-prostamide F(2), 0.5 and 0.03pmol, respectively. The LC/ESI/MS technique for measuring PGF synthase activity showed higher sensitivity than other methods. Using this method, we found that Bimatoprost, the ethyl amide analog of 17-phenyl-trinor PGF(2alpha) and an anti-glaucoma agent, inhibited all three reductase activities of PGF synthase when used at a low concentration. These results suggest that Bimatoprost also behaves as a potent PGF synthase inhibitor in addition to having prostamide-like activity.
Koda
Noriko
N
Division of Life Science, Graduate School of Integrated Science and Art, University of East Asia, 2-1 Ichinomiyagakuen-cho, Shimonoseki, Yamaguchi 751-8503, Japan.
Tsutsui
Yasutaka
Y
Niwa
Haruki
H
Ito
Seiji
S
Woodward
David F
DF
Watanabe
Kikuko
K
D000577:Amides; D000069580:Bimatoprost; D002853:Chromatography, Liquid / Q000379:methods*; D003008:Cloprostenol / Q000031:analogs & derivatives; D004791:Enzyme Inhibitors / Q000737:chemistry; D004795:Enzyme Stability; D006801:Humans; D006911:Hydroxyprostaglandin Dehydrogenases / Q000037:antagonists & inhibitors / Q000737:chemistry*; D008055:Lipids / Q000737:chemistry*; D015230:Prostaglandin D2 / Q000737:chemistry*; D011461:Prostaglandins F, Synthetic / Q000138:chemical synthesis*; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification; D015183:Restriction Mapping; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013379:Substrate Specificity
D000577:Amides; D004791:Enzyme Inhibitors; D008055:Lipids; D011461:Prostaglandins F, Synthetic; D011994:Recombinant Proteins; D003008:Cloprostenol; D006911:Hydroxyprostaglandin Dehydrogenases; C031051:prostaglandin-F synthase; D000069580:Bimatoprost; D015230:Prostaglandin D2