13-Hydroperoxylinoleic acid

Figure 7. Effect of free linoleic acid (LA) and 13-hydroxylinoleic acid on the lipoperoxidase activity of (1,2) non-selenic glutathione S-transferase from porcine liver and (3,4) Se-containing glutathione peroxidase from bovine erytrocytes (substrate - 25 mM 13-hydroperoxylinoleic acid). Here and in Fig.8 and 9, the enzyme activity in the abcence of free fatty acids was taken as 100% (1) and (3) in the presence of free linoleic acid (2) and (4) in the presence of 13-hydroxylinoleic acid [33].

Figure 6. Mechanism of cysteine-fatty acid adduct formation from the reaction of 13-hydroperoxylinoleic acid and cysteine in the absence of O2. The epoxyallylic radical at the top originates from the oxydiene radical of 13-hydroperoxylinoleic acid abbreviated structure) and RS is the cysteine thiyl radical. Reproduced with permission from Ref. 28.)...

Substrate Specificity. Hydroperoxide dehydrase from sunflower cotyledons was about four-fold more active wiA 13-hydroperoxylinoleic acid Aan 13-hydroperoxylinolenic acid. In contrast, leaf hydroperoxide lyase was more Aan 10-fold more active wiA 13-hydroperoxylinolenic acid Aan wiA 13-hydroperoxylinoleic acid. However, root hydroperoxide lyase showed no preference between Ae two substrates, again suggesting Aat roots have a different form of Ae enzyme Aan leaves. NeiAer 9-hydroperoxylinoleic nor 9-hydroperoxylinolenic acids were suitable substrates for any of Ae hydroperoxide metabolizing enzymes in sunflower. 

The advantage of a two-phase lipoxygenation system lies in three points. They include avoidance of inhibition by the substrate as well as high solubility of the substrate in the organic phase and product recovery in the aqueous phase. Drouet et al. [36] improved the production yield of hydroperoxylinoleic acid at high concentrations of linoleic acid in highly stirred borate buffer-octane biphasic medium. 

Verhagen, J.. Vliegenthart, J.F.G.. and Boldingh, J. 1978. Micelle and acid-soap formation of li-noleic acid and 13-L-hydroperoxylinoleic acid being substrates of lipoxygenase-1. Chem. Phys. Lipids 22 255-259. 

Brodowsky, I. D., Hamberg, M., and Oliw, E. H. 1992. A Linoleic-Acid (8r)-Dioxy-genase and Hydroperoxide Isomerase of the Fungus Gaeumannomyces-Graminis. Biosynthesis of (8r)-Hydroxylinoleic Acid and (7s,8s)-Dihydroxylinoleic Acid from (8r)-Hydroperoxylinoleic Acid. J. Biol. Chem., 267, 4738-14745. 

A number of peroxidases were investigated for their use in oxidizing organic sulfides, p-Substituted thioanisols were oxidized by partially purified soybean sulfox-idase using 13(S)-hydroperoxylinoleic acid as the peroxide. Methyl p-tolyl sulfide gave the (S)-sulfoxide with about 90% ee 121. 

Spin-trapping techniques have been used to study reactions of lipoxygenase with linoleic acid ( ). It was proposed that the formation of dimeric linoleic acid required the involvement of hydroperoxylinoleic acid ( ). The ESR spectrum from the interactions of the PUFA radical and the spin-trap indicated this involvement occurred Similar spin-trapping techniques could be used to investigate the possibility that DPE s may ultimately induce formation of various fatty acid dimers (e.g., dimers of linolenic acid). Formation of such polymers should dramatically affect membrane function. 

Hydroperoxylinoleic acid, see H-20101 2 -(3-Hydroperoxy-3-methyl-1 -butenyl)bruceol,... 

Brodowski, I.D. E.H. Oliw. 1993. Biosynthesis of 8R-hydroperoxylinoleic acid by the fungus Laetisaria arvalis. Biochim. Biophys. Acta 1168 68-72. 

Assaf, S., Hadar, Y., and Dosoretz, C.G., Biosynthesis of 13-hydroperoxylinoleate, 10-oxo-8-decenoic acid and l-octen-3-ol from linoleic acid by a mycelial-pellet homogenate of Pleurotus pulmonarius, J.Agric. Food Chem., 43, 2173, 1995. 

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