54739-30-9Relevant articles and documents
The acid-promoted reaction of ethyl linoleate with nitrite. New insights from 15N-labelling and peculiar reactivity of a model skipped diene
Napolitano, Alessandra,Crescenzi, Orlando,Camera, Emanuela,Giudicianni, Italo,Picardo, Mauro,D'Ischia, Marco
, p. 5061 - 5067 (2002)
The acid-promoted reaction of ethyl linoleate with nitrite ions was re-examined by an integrated approach based on the use of 15NO2- combined with extensive GC-MS (EI, NICI, PICI) and 2D 1H,15N and 1H,13C NMR analysis. The less polar products proved to be regioisomeric E-nitroalkenes, novel Z-nitroalkenes, and 3-nitro-1,5-hexadienes derivatives. A medium polarity fraction consisted mainly of stereo- and regioisomeric 1,2-nitronitrates along with 1,5-dinitro-1,3-pentadiene compounds. Novel 5-nitro-2,4-pentadienone products could be identified in the most polar fraction, which featured 1,2-nitroalcohols as the most abundant components. Under similar conditions 1,4-hexadiene gave mainly a nitrofuroxan derivative.
Catalytic production of oxo-fatty acids by lipoxygenases is mediated by the radical-radical dismutation between fatty acid alkoxyl radicals and fatty acid peroxyl radicals in fatty acid assembly
Takigawa, Yuta,Koshiishi, Ichiro
, p. 258 - 264 (2020/11/26)
Oxo-octadecadienoic acids (OxoODEs) act as peroxisome proliferator-activated receptor (PPAR) agonists biologically, and are known to be produced in the lipoxygenase/linoleate system. OxoODEs seem to originate from the linoleate alkoxyl radicals that are generated from (E/Z)-hydroperoxy octadecadienoic acids ((E/Z)HpODEs) by a pseudoperoxidase reaction that is catalyzed by ferrous lipoxygenase. However, the mechanism underlying the conversion of alkoxyl radical into OxoODE remains obscure. In the present study, we confirmed that OxoODEs are produced in the lipoxygenase/linoleate system in an oxygen-dependent manner. Interestingly, we revealed a correlation between the (E/Z)-OxoODEs content and the (E/E)-HpODEs content in the system. (E/E)-HpODEs could have been derived from (E/E)-linoleate peroxyl radicals, which are generated by the reaction between a free linoleate allyl radical and an oxygen molecule. Notably, the ferrous lipoxygenase-linoleate allyl radical (LOx(Fe2+)-L·) complex, which is an intermediate in the lipoxygenase/linoleate system, tends to dissociate into LOx(Fe2+) and a linoleate allyl radical. Subsequently, LOx(Fe2+) converts (E/Z)-HpODEs to an (E/Z)-linoleate alkoxyl radical through one-electron reduction. Taken together, we propose that (E/Z)-OxoODEs and (E/E)-HpODEs are produced through radical-radical dismutation between (E/Z)-linoleate alkoxyl radical and (E/E)-linoleate peroxyl radical. Furthermore, the production of (E/Z)OxoODEs and (E/E)-HpODEs was remarkably inhibited by a hydrophobic radical scavenger, 2,2,6,6-tetra-methylpiperidine 1-oxyl (TEMPO). On the contrary, water-miscible radical scavengers, 4-hydroxyl-2,2,6,6-tetramethylpiperidine 1-oxyl (OH-TEMPO) and 3-carbamoyl-2,2,5,5-tetramethyl-3-pyrroline-N-oxyl (CmΔP) only modestly or sparingly inhibited the production of (E/Z)-OxoODEs and (E/E)-HpODEs. These facts indicate that the radical-radical dismutation between linoleate alkoxyl radical and linoleate peroxyl radical proceeds in the interior of micelles.
Oxidation of C18 Hydroxy-Polyunsaturated Fatty Acids to Epoxide or Ketone by Catalase-Related Hemoproteins Activated with Iodosylbenzene
Teder, Tarvi,Boeglin, William E.,Brash, Alan R.
, p. 587 - 597 (2017/06/30)
Small catalase-related hemoproteins with a facility to react with fatty acid hydroperoxides were examined for their potential mono-oxygenase activity when activated using iodosylbenzene. The proteins tested were a Fusarium graminearum 41?kD catalase hemoprotein (Fg-cat, gene FGSG_02217), a Pseudomonas fluorescens Pfl01 catalase (37.5?kD, accession number WP_011333788.1), and a Mycobacterium avium ssp. paratuberculosis 33?kD catalase (gene MAP-2744c). 13-Hydroxy-octadecenoic acids (which are normally unreactive) were selected as substrates because these enzymes react specifically with the corresponding 13S-hydroperoxides (Pakhomova et al. 18:2559–2568, 5; Teder et al. 1862:706–715, 14). In the presence of iodosylbenzene Fg-cat converted 13S-hydroxy-fatty acids to two products: the 15,16-double bond of 13S-hydroxy α-linolenic acid was oxidized stereospecifically to the 15S,16R-cis-epoxide or the 13-hydroxyl was oxidized to the 13-ketone. Products were identified by UV, HPLC, LC–MS, NMR and by comparison with authentic standards prepared for this study. The Pfl01-cat displayed similar activity. MAP-2744c oxidized 13S-hydroxy-linoleic acid to the 13-ketone, and epoxidized the double bonds to form the 9,10-epoxy-13-hydroxy, 11,12-epoxy-13-hydroxy, and 9,10-epoxy-13-keto derivatives; equivalent transformations occurred with 9S-hydroxy-linoleic acid as substrate. In parallel incubations in the presence of iodosylbenzene, human catalase displayed no activity towards 13S-hydroxy-linoleic acid, as expected from the highly restricted access to its active site. The results indicated that with suitable transformation to Compound I, monooxygenase activity can be demonstrated by these catalase-related hemoproteins with tyrosine as the proximal heme ligand.
