Polyunsaturated fatty lipoxygenase

Lipoxygenase-Catalyzed Oxidations. Lipoxygenase-1 catalyzes the incorporation of dioxygen into polyunsaturated fatty acids possessing a l(Z),4(Z)-pentadienyi moiety to yield ( ),(Z)-conjugated hydroperoxides. A highly active preparation of the enzyme from soybean is commercially available in purified form. From a practical standpoint it is important to mention that the substrate does not need to be in solution to undergo the oxidation. Indeed, the treatment of 28 g/L of linoleic acid [60-33-3] with 2 mg of the enzyme results in (135)-hydroperoxide of linoleic acid in 80% yield... 

Chamirlitrat, W. and Mason, KP. (1989). Lipid preroxyl radical intermediates in the peroxidation of polyunsaturated fatty acids by lipoxygenase. J. Biol. Chem. 264, 20968—20973. 

Lipoxygenase (EC 1.13.11.12, nonheme iron dioxygenase), the substrate (polyunsaturated fatty acid) is poorly water soluble and the product (hydroperoxy-fatty acid) is hydrophilic. The reaction occurs in the aqueous phase [85,86]. 

The lipase-catalyzed fatty acid ester hydrolysis and the lipoxygenation of free polyunsaturated fatty acids are involved in the same lipid degradation pathway. They are respectively the first and second reaction in the lipoxygenase pathway (Fig. 3) [87-91]. The pathway produces volatile products of considerable importance in food technology including Cg[92, 93] or Cg- 94—96 aldehydes and alcohols from polyunsaturated fatty... 

The ability of free or immobilized lipoxygenase to introduce oxygen derived from the air into polyunsaturated fatty acids in media containing organic solvent and aqueous buffer has been investigated [9,56]. The influence of many parameters was tested upon the degree of oxygenation in biphasic systems [36,108]. 

A summary of the processes for producing the eicosanoids from the polyunsaturated fatty acid, arachidonic acid, is presented in Figure 11.27. The two enzymes separate for synthesising the prostanoids or the leucotrienes are cyclooxygenase and lipoxygenase, respectively. Whether prostanoids or leucotrienes are produced in any given tissue will depend on the relative activities of these two enzymes in that tissue. 

Lipoxygenase [EC 1.13.11.12] catalyzes the reaction of linoleate with dioxygen to produce (9Z,11 )-(135 )-13-hydroperoxyoctadeca-9,ll-dienoate. This iron-depen-dent enzyme can also oxidize other methylene-interrupted polyunsaturated fatty acids. See also specific enzyme... 

In 1990, Triantaphylidds and coworkers reported on the preparative enzymatic synthesis of hnoleic acid (135) hydroperoxide 24a using soybean lipoxygenase-1. In this dioxygenation asymmetry is induced by the catalyst, the enzyme. The reaction was later used by Dussault and also by Baba and coworkers as key step in the preparation of more complex peroxides. The enzyme is a non-heme iron dioxygenase which catalyzes the incorporation of dioxygen into polyunsaturated fatty acids to yield E,Z conjugated diene hydroperoxides 24a-d. With this enzymatic method, the hydroperoxide 24a could... 

Lipoxygenase (EC 1.13.11.12) is an enzyme that catalyzes the hydroperoxidation of polyunsaturated fatty acids and esters containing a cis-cis-l, 4-pentadiene system (Table 6). In 1947, Theorell et al. obtained the enzyme in a crystalline form from soybeans and reported that the enzyme neither contained nor required a metal cofactor192. Subsequent studies from three groups of investigators have demonstrated that the enzyme purified from soybeans in an iron-containing dioxygenase74-76 ... 

Madison, B. L. and Hughes, W. J. 1983. Improved lipoxygenase method for measuring cis, cis-methylene interrupted polyunsaturated fatty acids in fats and oils. J. Assoc. Anal. Chem. 66, 81-84. 

Lipoxygenases catalyze oxidation of polyunsaturated fatty acids in plant lipids. Within animal tissues the lipoxygenase-catalyzed reaction of arachidonic acid with 02 is the first step in formation of Ieukotrienes and other mediators of inflammation. These reactions are discussed in Chapter 21. 

Lipoxygenases, of which the enzyme from soy beans has been studied the most, also catalyze oxidation of polyunsaturated fatty acids in lipids as indicated in Eq. 21-17. Formation of the hydroperoxide product is accompanied by a shift of the double bond and conversion from cis to trans configuration. Soybean lipoxygenase is a member of a family of related lipoxygenases that are found in all eukaryotes. All... 

Lipoxygenase-Catalyzed Oxidations. Lipoxygenase-1 catalyzes the incorporation of diuxygen into polyunsaturated fatty acids possessing a l(Z).4(Z)-pentadienyl moiety to yield ( ).conjugated hydroperoxides. A highly active preparation of the enz.yme from soybean is commercially available in purified form. 

When a diet is rich in polyunsaturated fatty acids, the inflammatory response and production of free radicals appear to be strengthened. Arachidonic acid is held responsible for this reaction, as it is used by lipoxygenases of the immune system cells to produce, via biochemical transformations, leukotrienes, compounds which function as mediators and perform an important function in the immune system (Szponar and Respondek 1998, Fimmel and Zouboulis 2005). 

The volatile fraction of good quality oils is mainly formed by compounds produced enzymatically from polyunsaturated fatty acids through the lipoxygenase (LOX) pathway. Aldehydes (C6), alcohols (C6) and their corresponding esters are the most abundant products (Figure 2.7). 

Some polyunsaturated fatty acids were tested for the production of hydroxy fatty acids by PR3 because polyunsaturated fatty acids contained a, 4-ds,cis-diene unit which could serve as a key structural element for the hydroxylation by lipoxygenase. When eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) carrying l,4-d c y-diene unit were used as substrates for bioconversion by PR3, new products were detected on TLC analysis as shown in... 

Lipoxygenases. Lipoxygenases catalyze the peroxidation of polyunsaturated fatty acids with a cis.cis 1-4-pentadiene moiety to form conjugated diene hydroperoxides (Figure lc). Free fatty acids are formed following wounding from the deacylation of membrane... 

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