Novel reversible, irreversible and fluorescent inhibitors of platelet-activating factor acetylhydrolase as mechanistic probes
Phosphatidylcholines (1-O-alcoxy-2-amino-2-desoxy-phosphocholines and 1-pyrene-labeled analogs) were synthesized and used to examine interactions with recombinant human PAF-acetylhydrolase (PAF-AH), an enzyme purified from plasma, and with macrophage-like U937 cells. Novel phosphatidylcholines conta...
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| Main Authors: | , , , , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
20 May 1999
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| In: |
Atherosclerosis
Year: 1999, Volume: 144, Issue: 1, Pages: 79-90 |
| ISSN: | 1879-1484 |
| DOI: | 10.1016/S0021-9150(99)00034-9 |
| Online Access: | Verlag, Volltext: http://dx.doi.org/10.1016/S0021-9150(99)00034-9 Verlag, Volltext: http://www.sciencedirect.com/science/article/pii/S0021915099000349 
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| Author Notes: | Hans P. Deigner, Ralf Kinscherf, Ralf Claus, Beatrix Fyrnys, Christopher Blencowe, A. Hermetter |
| Summary: | Phosphatidylcholines (1-O-alcoxy-2-amino-2-desoxy-phosphocholines and 1-pyrene-labeled analogs) were synthesized and used to examine interactions with recombinant human PAF-acetylhydrolase (PAF-AH), an enzyme purified from plasma, and with macrophage-like U937 cells. Novel phosphatidylcholines containing a sn-2-carbamoylester group such as 1-O-hexadecyl-2-desoxy-2-amino-methylcarbamoyl-2-methyl-rac-glycero-3-phosphocholine 11 were found to act as site-specific irreversible enzyme inhibitors with Ki-values up to 83 (Kirev) and 177 (Ki(inact)) μm. The compounds exhibit only marginal inhibition of Ca2+-dependent phospholipases. Kinetic data show that phosphocholines carrying a terminal sn-1-pyrene moiety inhibit PAF-AH activity with an effectivity similar to analogs with an aliphatic chain. 1-O-Decyloxy-[10-(4-pyrenyl)-butoxy]-2-desoxy-2-amino-carbamoyl-methyl-rac-glycero-3-phosphocholine 13 could be used for enzyme labeling and to demonstrate an inhibitor-enzyme stoichiometry of 0.7:1. At 8°C, the compound accumulated in the membranes of U937 cells, at 37°C it was internalized into intracellular compartments. Structure-activity studies in a mixed micelle assay indicated that the inhibition power of reversible and irreversible inhibitors increases along with the (sn)-1-chain length similar to the structure-dependent binding of ether phospholipids to the PAF-receptor. Unlike the situation at the (sn)-1-position, increasing chain length at the sn-2-position, or an alkyl branching of the glycerol backbone significantly reduced the inhibitory potency. |
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| Item Description: | Gesehen am 14.09.2017 |
| Physical Description: | Online Resource |
| ISSN: | 1879-1484 |
| DOI: | 10.1016/S0021-9150(99)00034-9 |