868364-06-1Relevant articles and documents
Identification and Quantitation of C=C Location Isomers of Unsaturated Fatty Acids by Epoxidation Reaction and Tandem Mass Spectrometry
Zhao, Yaoyao,Zhao, Hansen,Zhao, Xu,Jia, Jia,Ma, Qiang,Zhang, Sichun,Zhang, Xinrong,Chiba, Hitoshi,Hui, Shu-Ping,Ma, Xiaoxiao
, p. 10270 - 10278 (2017)
Unsaturated fatty acids (FAs) serve as nutrients, energy sources, and signaling molecules for organisms, which are the major components for a large variety of lipids. However, structural characterization and quantitation of unsaturated FAs by mass spectrometry remain an analytical challenge. Here, we report the coupling of epoxidation reaction of the C=C in unsaturated FAs and tandem mass spectrometry (MS) for rapid and accurate identification and quantitation of C=C isomers of FAs in a shotgun lipidomics approach. Epoxidation of the C=C leads to the production of an epoxide which, upon collision induced dissociation (CID), produces abundant diagnostic ions indicative of the C=C location. The total intensity of the same set of diagnostic ions for one specific FA C=C isomer was also used for its relative and absolute quantitation. The simple experimental setup, rapid reaction kinetics (90% for monounsaturated FAs), and easy-to-interpret tandem MS spectra enable a promising methodology particularly for the analysis of unsaturated FAs in complex biological samples such as human plasma and animal tissues.
Epoxidation, hydroxylation and aromatization is catalyzed by a peroxygenase from Solanum lycopersicum
Fuchs, Christopher,Schwab, Wilfried
, p. 52 - 60 (2013/10/22)
Plant peroxygenase (PXG) oxidizes unsaturated fatty acids by transferring an oxygen atom of a hydroperoxide to the double bond, thereby providing epoxides. In this work we investigated the potential of a PXG from tomato (Solanum lycopersicum, SlPXG) to catalyze the oxidation of a variety of natural products. A SlPXG gene was cloned from tomato, heterologously expressed in yeast and the membrane bound recombinant SlPXG protein was used as enzyme source. Unsaturated fatty acids, fatty acid derivatives, and terpenes were epoxidized by SlPXG in the presence of various hydroperoxides exclusively at their cis-double bonds. Terpenes with p-menthene skeleton were transformed in different ways depending on their molecular structures. R-(+)- and S-(-)-limonene were converted to R-(+)-limonene-trans-1,2-epoxide (97%) and cis-S-(-)-limonene-1,2- epoxide (88%), respectively whereas α-terpinenewas hydroxylated to cis-1,4-dihydroxy-p-menth-2-ene and γ-terpinene was aromatized to p-cymene. In the last reaction the hydroperoxide served as hydrogen acceptor rather than an oxygen donor. PXG appears to be a versatile biocatalyst able to perform different kinds of oxidation reactions. As no cofactors like NAD(P)H are required and H2O2is an environmentally friendly oxidant, PXG enables new applications for the synthesis of fine chemicals from renewable resources.
Epoxidation of polyunsaturated fatty acid double bonds by dioxirane reagent: Regioselectivity and lipid supramolecular organization
Grabovskiy, Stanislav A.,Kabal'nova, Natalia N.,Chatgilialoglu, Chryssostomos,Ferreri, Carla
, p. 2243 - 2253 (2007/10/03)
The use of dimethyldioxirane (DMD) as the epoxidizing agent for polyunsaturated fatty acids was investigated. With fatty acid methyl esters, this is a convenient method for avoiding acidic conditions, using different solvents, and simplifying the isolation procedures, with less contamination due to by-products. The reagent was also tested with free fatty acids in water. In this case, the supramolecular organization of fatty acids influenced the reaction outcome, and the epoxidation showed interesting regioselective features. The C=C bonds closest to the aqueous-micelle interface is the most favored for the interaction with dimethyldioxirane. The preferential epoxidation of linoleic acid (=(9Z,12Z)-octadeca-9,12-dienoic acid) to the 9,10-monoepoxy derivative was achieved, with a high yield and 65% regioselectivity. In case of arachidonic acid (=(5Z,8Z,11Z,14Z)-eicosa-5,8,11,14-tetraenoic acid) micelles, the regioselective outcome with formation of the four possible monoepoxy isomers was studied under different conditions. It resulted to be a convenient synthesis of 'cis-5,6-epoxyeicosatrienoic acid' (=3-[(2Z,5Z,8Z)-tetradeca-2,5,8- trienyl]oxiran-2-butanoic acid), whereas in reverse micelles, epoxidation mostly gave 'cis-14,15-epoxyeicosatrienoic acid (= (5Z,8Z,11Z)-13-(3-pentyloxiran-2- yl)trideca-5,8,11-trienoic acid).
