18320-18-8Relevant articles and documents
Kinetic isotope effects in the oxidation of arachidonic acid by soybean lipoxygenase-1
Jacquot, Cyril,Peng, Sheng,van der Donk, Wilfred A.
, p. 5959 - 5962 (2008)
The reaction of soybean lipoxygenase-1 with linoleic acid has been extensively studied and displays very large kinetic isotope effects. In this work, substrate and solvent kinetic isotope effects as well as the viscosity dependence of the oxidation of arachidonic acid were investigated. The hydrogen atom abstraction step was rate-determining at all temperatures, but was partially masked by a viscosity-dependent step at ambient temperatures. The observed KIEs on kcat were large (～100 at 25 °C).
The autooxidation process in linoleic acid screened by Raman spectroscopy
MacHado,De Carvalho, L. A. E. Batista,Otero,Marques
, p. 1991 - 2000 (2012)
The chemical changes associated to the autooxidation process of linoleic acid (LA) were detected by Raman spectroscopy and interpreted in the light of density functional theory (DFT) calculations performed for both the fatty acid and its main oxidation products. The present methodology, applied for a six-day period upon induction of oxidation (through heating), allowed to understand the chemical modifications occurring during the oxidation process. Raman spectroscopy was shown to be a suitable and reliable technique for assessing the oxidation degree of fatty acid samples, particularly pure fatty acids, mainly when computational methods are used alongside to predict the spectral features of the distinct chemical entities involved. Screening of the oxidation process was mostly based on the loss of intensity of the bands assigned to LA cis-double bonds. Copyright
Enantioselective formation of an α, β-epoxy alcohol by reaction of methyl 13(S)-hydroperoxy-9(Z),11(E)-octadecadienoate with titanium isopropoxide
Piazza,Foglia,Nunez
, p. 1385 - 1390 (1997)
Methyl 11(R), 12(R)-epoxy-13(S)-hydroxy-9(Z)-octadecenoate (threo isomer) was generated from linoleic acid by the sequential action of an enzyme and two chemical reagents. Linoleic acid was treated with lipoxygenase to yield its corresponding hydroperoxide [13(S)-hydroperoxy-9(Z),11(E)-octadecadienoic acid]. After methylation with CH2N2, the hydroperoxide was treated with titanium (IV) isopropoxide [Ti(O-i-Pr)4] at 5 °C for 1 h. The products were separated by normal-phase high-performance liquid chromatography and characterized with gas chromatography-mass spectrometry, infrared spectroscopy, and nuclear magnetic resonance spectroscopy. Approximately 30% of the product was methyl 13(S)-hydroxy-9(Z),11(E)-octadecadienoate. Over 60% of the isolated product was methyl 11(R),12(R)-epoxy-13(S)-hydroxy-9(Z)-octadecenoate. After quenching Ti(O-i-Pr)4 with water, the spent catalyst could be removed from the fatty products by partitioning between CH2Cl2 and water. These results demonstrate that Ti(O-i-Pr)4 selectively promotes the formation of an α-epoxide with the threo configuration. It was critically important to start with dry methyl 13(S)-hydroperoxy-9(Z),11(E)-octadecadienoate because the presence of small amounts of water in the reaction medium resulted in the complete hydrolysis of epoxy alcohol to trihydroxy products.
The hydroperoxide moiety of aliphatic lipid hydroperoxides is not affected by hypochlorous acid
Zschaler, Josefin,Arnhold, Juergen
, p. 42 - 51 (2014)
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.
Synthesis of 13R,20-dihydroxy-docosahexaenoic acid by site-directed mutagenesis of lipoxygenase derived from Oscillatoria nigro-viridis PCC 7112
Yi, Jong-Jae,Heo, Sun-Yeon,Ju, Jung-Hyun,Oh, Baek-Rock,Son, Woo Sung,Seo, Jeong-Woo
, p. 893 - 898 (2020)
Lipoxygenases (LOXs) are implicated in the biosynthesis of pro- and anti-inflammatory lipid mediators involved in immune cell signaling, most of which catalyze peroxidation of polyunsaturated fatty acids by distinct regio- and stereoselectivity. Current reports suggested that conserved amino acid, Gly in R-LOXs and Ala in S-LOXs, in the catalytic domain play an important role in determining the position as well as the stereochemistry of the functional group. Recently, we have confirmed that the catalytic specificity of cyanobacterial lipoxygenase, named Osc-LOX, with alanine at 296 was 13S-type toward linoleic acid, and producing a 17S- hydroxy-docosahexaenoic acid from docosahexaenoic acid (DHA). Here, we aimed to change the catalytic property of LOX from13S-LOX to 9R-LOX by replacing Ala with Gly and to produce a lipid mediators different from the wild-type using DHA. Finally, we succeeded in generating human endogenous a 13R-hydroxy-docosahexaenoic acid and a 13R,20-dihydroxy-docosahexaenoic acid from DHA through an enzymatic reaction using the Osc-LOX-A296G. Our study could enable physiological studies and pharmaceutical research for the 13R,20-dihydroxy-docosahexaenoic acid.
LOXPsa1, the first recombinant lipoxygenase from a basidiomycete fungus
Plagemann, Ina,Zelena, Katerina,Arendt, Philipp,Ringel, Peter D.,Krings, Ulrich,Berger, Ralf G.
, p. 99 - 104 (2013)
A dioxygenase from the edible basidiomycete Pleurotus sapidus, originally researched because of its distinct ability to convert the sequiterpene (+)-valencene to the valuable grapefruit aroma (+)-nootkatone, was identified as a potent lipoxygenase (LOXsu
Steric control of oxygenation regiochemistry in soybean lipoxygenase-1
Knapp,Seebeck,Klinman
, p. 2931 - 2932 (2001)
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Reactivity of lysine moieties toward an epoxyhydroxylinoleic acid derivative: Aminolysis versus hydrolysis
Lederer, Markus O.,Schuler, Axel,Ohmenhaeuser, Marc
, p. 4611 - 4620 (1999)
Epoxyols are generally accepted as crucial intermediates in lipid oxidation. The reactivity of tertbutyl (9R*,10S*,11E,13S)-9,10-epoxy-13- hydroxy-11-octadecenoate (11a,b) toward lysine moieties is investigated, employing N2-acetyllysine 4-methylcoumar-7-ylamide (12) as a model for protein-bound lysine. The prefixes R* and S* denote the relative configuration at the respective stereogenic centers. Independent synthesis and unequivocal structural characterization are reported for 11a,b, its precursors, and tert-butyl (9R*,10R*,11E,13S)-10-({5-(acetylamino)-6-[(4- methyl-2-oxo-2H-chromen-7-yl)amino]-6-oxohexyl}amino)-9,13-dihydroxy-11- octadecenoate (13a-d). Reactions of 11a,b and 12 in 1-methyl-2-pyrrolidone (MP) and MP/water mixtures at pH 7.4 and 37 °C for 56 days show formation of the aminols 13a-d to be favored by an increased water content. The same trend is observed for hydrolytic cleavage of 11a,b to tert-butyl (E)-9,10,13- trihydroxy-11-octadecenoate (14) and tert-butyl (E)-9,12,13-trihydroxy-10- octadecenoate (15). Under the given conditions, aminolysis proceeds via an S(N)2 substitution, in contrast with the S(N)1 process for hydrolysis. In the MP/water (8:2) incubation, 15.8% of 12 has been transformed to 13a-d and 10.5% of 11a,b hydrolyzed to the regioisomers 14 and 15 after 8 weeks, respectively. Aminolysis of α,β-unsaturated epoxides by lysine moleties therefore is expected to be an important mode of interaction between proteins and lipid oxidation products.
Experimental evidence for hydrogen tunneling when the isotopic arrhenius prefactor (Ah/Ad) is unity
Sharma, Sudhir C.,Klinman, Judith P.
, p. 17632 - 17633 (2008)
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The CYP74B and CYP74D divinyl ether synthases possess a side hydroperoxide lyase and epoxyalcohol synthase activities that are enhanced by the site-directed mutagenesis
Gorina, Svetlana S.,Grechkin, Alexander N.,Iljina, Tatiana M.,Mukhtarova, Lucia S.,Smirnova, Elena O.,Toporkova, Yana Y.
, (2020/09/16)
The CYP74 family of cytochromes P450 includes four enzymes of fatty acid hydroperoxide metabolism: allene oxide synthase (AOS), hydroperoxide lyase (HPL), divinyl ether synthase (DES), and epoxyalcohol synthase (EAS). The present work is concerned with catalytic specificities of three recombinant DESs, namely, the 9-DES (LeDES, CYP74D1) of tomato (Solanum lycopersicum), 9-DES (NtDES, CYP74D3) of tobacco (Nicotiana tabacum), and 13-DES (LuDES, CYP74B16) of flax (Linum usitatissimum), as well as their alterations upon the site-directed mutagenesis. Both LeDES and NtDES converted 9-hydroperoxides of linoleic and α?linolenic acids to divinyl ethers colneleic and colnelenic acids (respectively) with only minorities of HPL and EAS products. In contrast, LeDES and NtDES showed low efficiency towards the linoleate 13-hydroperoxide, affording only the low yield of epoxyalcohols. LuDES exhibited mainly the DES activity towards α?linolenate 13-hydroperoxide (preferred substrate), and HPL activity towards linoleate 13-hydroperoxide, respectively. In contrast, LuDES converted 9-hydroperoxides primarily to the epoxyalcohols. The F291V and A287G mutations within the I-helix groove region (SRS-4) of LuDES resulted in the loss of DES activity and the acquirement of the epoxyalcohol synthase activity. Thus, the studied enzymes exhibited the versatility of catalysis and its qualitative alterations upon the site-directed mutagenesis.
