- Stereocontrolled Total Synthesis of (5Z,8Z,11Z,13E)(15S)-15-Hydroxyeicosa-5,8,11,13-tetraenoic Acid (15S-HETE) and Analogues
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A novel and stereoselective synthesis of 15S-HETE and a number of analogues based on a Cu(I)-Pd(0) coupling reaction is described.
- Nicolaou, K. C.,Ladduwahetty, Tamara,Elisseou, E. Michael
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- Crystal structure of a lipoxygenase in complex with substrate: The arachidonic acid-binding site of 8R-lipoxygenase
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Lipoxygenases (LOX) play critical roles in mammalian biology in the generation of potent lipid mediators of the inflammatory response; consequently, they are targets for the development of isoform-specific inhibitors. The regio- and stereo-specificity of the oxygenation of polyunsaturated fatty acids by the enzymes is understood in terms of the chemistry, but structural observation of the enzyme-substrate interactions is lacking. Although several LOX crystal structures are available, heretofore the rapid oxygenation of bound substrate has precluded capture of the enzyme-substrate complex, leaving a gap between chemical and structural insights. In this report, we describe the 2.0 ? resolution structure of 8R-LOX in complex with arachidonic acid obtained under anaerobic conditions. Subtle rearrangements, primarily in the side chains of three amino acids, allow binding of arachidonic acid in a catalytically competent conformation. Accompanying experimental work supports a model in which both substrate tethering and cavity depth contribute to positioning the appropriate carbon at the catalytic machinery.
- Neau, David B.,Bender, Gunes,Boeglin, William E.,Bartlett, Sue G.,Brash, Alan R.,Newcomer, Marcia E.
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p. 31905 - 31913
(2015/02/19)
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- The hydroperoxide moiety of aliphatic lipid hydroperoxides is not affected by hypochlorous acid
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The oxidation of polyunsaturated fatty acids to the corresponding hydroperoxide by plant and animal lipoxygenases is an important step for the generation of bioactive lipid mediators. Thereby fatty acid hydroperoxide represent a common intermediate, also in human innate immune cells, like neutrophil granulocytes. In these cells a further key component is the heme protein myeloperoxidase producing HOCl as a reactive oxidant. On the basis of different investigation a reaction of the fatty acid hydroperoxide and hypochlorous acid (HOCl) could be assumed. Here, chromatographic and spectrometric analysis revealed that the hydroperoxide moiety of 15S-hydroperoxy-5Z,8Z,11Z,13E-eicosatetraenoic acid (15-HpETE) and 13S-hydroperoxy-9Z,11E-octadecadienoic acid (13-HpODE) is not affected by HOCl. No reduction of the hydroperoxide group due to a reaction with HOCl could be measured. It could be demonstrated that the double bonds of the fatty acid hydroperoxides are the major target of HOCl, present either as reagent or formed by the myeloperoxidase-hydrogen peroxide-chloride system.
- Zschaler, Josefin,Arnhold, Juergen
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- Manufacture of (5Z,8Z,11Z,13E)(15S)-15-hydroxyeicosa-5,8,11,13-tetraenoic acid sodium salt for clinical trials
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A robust synthesis of (5Z,8Z,11Z,13E)(15S)-15-hydroxyeicosa-5,8,11,13- tetraenoic acid (15(S)-HETE) sodium salt was established, utilising a biooxidation process. Treatment of arachidonic acid with soybean lipoxidase in 0.1 M sodium tetraborate buffer under oxygen pressure resulted in formation of the hydroperoxide, 15(S)-HPETE. Addition of sodium borohydride to the reaction mixture reduced the hydroperoxide to 15(S)-HETE, which was then purified by column chromatography. 15(S)-HETE sodium salt was prepared by treatment of an ethanol solution of HETE with aqueous sodium hydrogen carbonate. Multiple 10-g batches of 15(S)-HETE sodium salt with >98% enantiomeric excess and >98% chemical purity were prepared to support clinical trials.
- Harrison, Paul,Jackson, Mark,Jones, Shaun,Kronig, Christel,Lennon, Ian C.,Simmonds, Shaun,Conrow, Raymond E.
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p. 301 - 304
(2011/09/20)
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- Physcomitrella patens has lipoxygenases for both eicosanoid and octadecanoid pathways
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Mosses have substantial amounts of long chain C20 polyunsaturated fatty acids, such as arachidonic and eicosapentaenoic acid, in addition to the shorter chain C18 α-linolenic and linoleic acids, which are typical substrates of lipoxygenases in flowering p
- Anterola, Aldwin,G?bel, Cornelia,Hornung, Ellen,Sellhorn, George,Feussner, Ivo,Grimes, Howard
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experimental part
p. 40 - 52
(2009/07/11)
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- 9-Hydroxy-10,12-octadecadienoic acid (9-HODE) and 13-hydroxy-9,11-octadecadienoic acid (13-HODE): Excellent markers for lipid peroxidation
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Various conditions for conversion of (9S,10E,12Z)-9-hydroperoxy-10,12-octadecadienoic acid (9S-HPODE) and (13S,9Z,10E)-13-hydroperoxy-9,11-octadecadienoic acid (13S-HPODE) into the corresponding hydroxy acids, (9S,10E,12Z)-9-hydroxy-10,12-octadecadienoic acid (9S-HODE) and (13S,9Z,10E)-13-hydroxy-9,11-octadecadienoic acid (13S-HODE), were investigated in vitro. 9S-HODE and 13S-HODE were subjected to lipid peroxidation under various conditions: oxidation was carried out in air only, and in air/Fe2+/ascorbate, air/H2O2/Fe2+, air/Fe2+, and air/Fe3+. In contrast to the corresponding hydroperoxides (9S-HPODE and 13S-HPODE), 9-HODE and 13-HODE proved to be stable in all these oxidation experiments. Unexpectedly, hydroxy compounds obtained by reduction of hydroperoxides derived from arachidonic acid were not attacked by air/Fe2+/ascorbate or air/Fe2+. Thus, for instance, (15S,5Z,8Z,11Z,13E)-15-hydroxy-5,8,11,13-eicosatetraenoic acid (15-HETE) remained unchanged in spite of possessing the structural prerequisites for attack by radicals, i.e. a CH2-group located between two double bonds. Consequently, metal-induced air oxidation reactions of these systems seem to be restricted to hydroperoxides of unsaturated acids (LOOH) and not to corresponding hydroxy compounds (LOH). The reported experiments explain why hydroxy derivatives of unsaturated acids, especially 9-HODE and 13-HODE, are enriched in naturally occurring lipid peroxidation (LPO) processes to a greater extent than any other LPO product and why they are nearly ideal markers for LPO.
- Spiteller, Peter,Spiteller, Gerhard
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p. 131 - 139
(2007/10/03)
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