Stereospecific Inhibition of CETP by Chiral N,N-Disubstituted Trifluoro-3-amino-2-propanols
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- 作者：Daniel T. Connolly ; Bryan J. Witherbee ; Michele A. Melton ; Richard C. Durley ; Margaret L. Grapperhaus ; Brad R. McKinnis ; William F. Vernier ; Maribeth A. Babler ; Jeng-Jong Shieh ; Mark E. Smith ; and Jam
- 刊名：Biochemistry
- 出版年：2000
- 出版时间：November 14, 2000
- 年：2000
- 卷：39
- 期：45
- 页码：13870 - 13879
- 全文大小：126K
- 年卷期：v.39,no.45(November 14, 2000)
- ISSN：1520-4995
文摘
Chiral N,N-disubstituted trifluoro-3-amino-2-propanols represent a recently discovered classof compounds that inhibit the neutral lipid transfer activity of cholesteryl ester transfer protein (CETP).These compounds all contain a single chiral center that is essential for inhibitory activity. (R,S)SC-744,which is composed of a mixture of the two enantiomers, inhibits CETP-mediated transfer of [3H]cholesterylester ([3H]CE) from HDL donor particles to LDL acceptor particles with an IC50 = 200 nM when assayedusing a reconstituted system in buffer and with an IC50 = 6 
M when assayed in plasma. Upon isolationof the enantiomers, it was found that the (R,+) enantiomer, SC-795, was about 10-fold more potent thanthe mixture, and that the (S,-) enantiomer, SC-794, did not have significant inhibitory activity (IC50 >0.8 M). All of the activity of the (S,-)SC-794 enantiomer could be accounted for by contamination ofthis sample with a residual 2% of the highly potent (R,+) enantiomer, SC-795. The IC50 of (R,+)SC-795,20 nM, approached the concentration of CETP (8 nM) in the buffer assay. These chiral N,N-disubstitutedtrifluoro-3-amino-2-propanols were found to associate with both LDL and HDL, but did not disrupt overalllipoprotein structure. They did not affect the on or off rates of CETP binding to HDL disk particles.Inhibition was highly specific since the activities of phospholipid transfer protein and lecithin cholesterolacyl transferase were not affected. Competition experiments showed that the more potent enantiomer(R)SC-795 prevented cholesteryl ester binding to CETP, and direct binding experiments demonstratedthat this inhibitor bound to CETP with high affinity and specificity. It is estimated, based on the relativeconcentrations of inhibitor and lipid in the transfer assay, that (R)SC-795 binds approximately 5000-foldmore efficiently to CETP than the natural ligand, cholesteryl ester. We conclude that these chiral N,N-disubstituted trifluoro-3-amino-2-propanol compounds do not affect lipoprotein structure or CETP-lipoprotein recognition, but inhibit lipid transfer by binding to CETP reversibly and stereospecifically ata site that competes with neutral lipid binding.
M when assayed in plasma. Upon isolationof the enantiomers, it was found that the (R,+) enantiomer, SC-795, was about 10-fold more potent thanthe mixture, and that the (S,-) enantiomer, SC-794, did not have significant inhibitory activity (IC50 >0.8 M). All of the activity of the (S,-)SC-794 enantiomer could be accounted for by contamination ofthis sample with a residual 2% of the highly potent (R,+) enantiomer, SC-795. The IC50 of (R,+)SC-795,20 nM, approached the concentration of CETP (8 nM) in the buffer assay. These chiral N,N-disubstitutedtrifluoro-3-amino-2-propanols were found to associate with both LDL and HDL, but did not disrupt overalllipoprotein structure. They did not affect the on or off rates of CETP binding to HDL disk particles.Inhibition was highly specific since the activities of phospholipid transfer protein and lecithin cholesterolacyl transferase were not affected. Competition experiments showed that the more potent enantiomer(R)SC-795 prevented cholesteryl ester binding to CETP, and direct binding experiments demonstratedthat this inhibitor bound to CETP with high affinity and specificity. It is estimated, based on the relativeconcentrations of inhibitor and lipid in the transfer assay, that (R)SC-795 binds approximately 5000-foldmore efficiently to CETP than the natural ligand, cholesteryl ester. We conclude that these chiral N,N-disubstituted trifluoro-3-amino-2-propanol compounds do not affect lipoprotein structure or CETP-lipoprotein recognition, but inhibit lipid transfer by binding to CETP reversibly and stereospecifically ata site that competes with neutral lipid binding.