Micelle and acid-soap formation of linoleic acid and 13-L-hydroperoxylinoleic acid being substrates of lipoxygenase-1

Verhagen, Jan; Vliegenthart, Johannes F.G.; Boldingh, J.

doi:10.1016/0009-3084(78)90014-2

Cited by 49 publications

(35 citation statements)

References 10 publications

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“…The determination of callose synthase activity revealed that the unsaturated FFAs oleic (18:1), linoleic (18:2), and a-linolenic (18:3) acids inhibited callose synthesis in in vitro as well as in planta assays at similar concentrations to those reported for soybean (Kauss and Jeblick, 1986). Moreover, the FFA concentrations were below the critical micelle concentration (Verhagen et al, 1978;Murakami et al, 1986; Sellhorn (18:3). B, FFA concentrations in wheat spikelets inoculated with F. graminearum wild type (F.g. wt) and the lipase-deficient mutant Dfgl1-2 (F.g. Dfgl1-2).…”

Section: Discussionmentioning

confidence: 93%

Secreted Fungal Effector Lipase Releases Free Fatty Acids to Inhibit Innate Immunity-Related Callose Formation during Wheat Head Infection

Blümke

Falter

Herrfurth³

et al. 2014

Plant Physiology

112

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The deposition of the (1,3)-b-glucan cell wall polymer callose at sites of attempted penetration is a common plant defense response to intruding pathogens and part of the plant's innate immunity. Infection of the Fusarium graminearum disruption mutant Dfgl1, which lacks the effector lipase FGL1, is restricted to inoculated wheat (Triticum aestivum) spikelets, whereas the wild-type strain colonized the whole wheat spike. Our studies here were aimed at analyzing the role of FGL1 in establishing full F. graminearum virulence. Confocal laser-scanning microscopy revealed that the Dfgl1 mutant strongly induced the deposition of spot-like callose patches in vascular bundles of directly inoculated spikelets, while these callose deposits were not observed in infections by the wild type. Elevated concentrations of the polyunsaturated free fatty acids (FFAs) linoleic and a-linolenic acid, which we detected in F. graminearum wild type-infected wheat spike tissue compared with Dfgl1-infected tissue, provided clear evidence for a suggested function of FGL1 in suppressing callose biosynthesis. These FFAs not only inhibited plant callose biosynthesis in vitro and in planta but also partially restored virulence to the Dfgl1 mutant when applied during infection of wheat spikelets. Additional FFA analysis confirmed that the purified effector lipase FGL1 was sufficient to release linoleic and a-linolenic acids from wheat spike tissue. We concluded that these two FFAs have a major function in the suppression of the innate immunity-related callose biosynthesis and, hence, the progress of F. graminearum wheat infection.

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Section: Discussionmentioning

confidence: 93%

Secreted Fungal Effector Lipase Releases Free Fatty Acids to Inhibit Innate Immunity-Related Callose Formation during Wheat Head Infection

Blümke

Falter

Herrfurth³

et al. 2014

Plant Physiology

112

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“…All reactions were performed at 25 O C in a 0.1 M sodium borate buffer, pH 10 (BB10). At pH 10, the critical micelle concentration of linoleate is (Verhagen et al, 1978b), and lipoxygenase-1 from soybeans has maximum activity. Reactions were carried out at final lipoxygenase concentrations of 1.3 pM or 12.5 nM; the final linoleate concentrations were 10, 50, or 100 pM.…”

Section: Methodsmentioning

confidence: 99%

The Dioxygenation Rate In Lipoxygenase Catalysis Is Determined by the Amount of Iron(III) Lipoxygenase in Solution

Schilstra¹,

Veldink²,

1994

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ABSTRACT:The dioxygenation rate in reactions catalyzed by lipoxygenase-1 from soybeans has been measured as a function of the enzyme present in the Fe(II1) form with rapid kinetic techniques. The experiments were carried out at p H 10, 25 "C. The product concentration and the fraction of iron(II1) lipoxygenase were monitored by measuring the absorbance at 243 nm and the tryptophan fluorescenceat 330 nm (excitation at 287 nm), respectively. In reactions started with 1.3 p M iron(I1) lipoxygenase and 9 p M linoleate, the initial rate, Qnit (estimated from the increase in absorbance over the initial 0.02 s of the reaction), is very small (4 SKI). In contrast, when the reactions are started with 1.3 p M iron(II1) lipoxygenase, Qnit is large (1 50 s-l). In reactions started with mixtures of iron(I1) and iron(II1) lipoxygenase, finit is linearly related to the initial concentration of the Fe(II1) enzyme form. Redistributions of the Fe(I1) and Fe(II1) enzyme forms during the reaction with 12 nM enzyme and 10,50, or 100 p M linoleate appear to be directly reflected in changes in the dioxygenation rate. The observations provide solid evidence for the hypothesis that only iron(II1) lipoxygenase can catalyze the hydrogen abstraction step in the dioxygenation reaction, and thus can be regarded as the active enzyme species. The observed dynamics are accurately predicted by a nonallosteric, two-step model for lipoxygenase catalysis [Schilstra et al. (1 992) Biochemistry 31, 7692-76991,

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“…The CMCs for 23a and 23d at the assay conditions (50 mM Tris buffer, 2 mM EDTA and 2 mM CaCl 2 , pH 7.5, R.T.) are, respectively, 628 μM and 395 μM (Figure 2B,C) which indicate that micelle formation does not occur at concentrations employed for inhibition or activation of h-5-LOX. In addition, we found a CMC value for linoleic acid of 185 μM (Figure 2A) [43], which demonstrates that the substrate concentration in the inhibition studies (100 μM) was below the CMC.…”

Section: Resultsmentioning

confidence: 99%

Discovery of a novel activator of 5-lipoxygenase from an anacardic acid derived compound collection

Wisastra

Kok

Eleftheriadis

et al. 2013

Bioorganic & Medicinal Chemistry

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Lipoxygenases (LOXs) and cyclooxygenases (COXs) metabolize poly-unsaturated fatty acids into inflammatory signaling molecules. Modulation of the activity of these enzymes may provide new approaches for therapy of inflammatory diseases. In this study, we screened novel anacardic acid derivatives as modulators of human 5-LOX and COX-2 activity. Interestingly, a novel salicylate derivative 23a was identified as a surprisingly potent activator of human 5-LOX. This compound showed both non-competitive activation towards the human 5-LOX activator adenosine triphosphate (ATP) and non-essential mixed type activation against the substrate linoleic acid, while having no effect on the conversion of the substrate arachidonic acid. The kinetic analysis demonstrated a non-essential activation of the linoleic acid conversion with a KA of 8.65 μM, αKA of 0.38 μM and a β value of 1.76. It is also of interest that a comparable derivative 23d showed a mixed type inhibition for linoleic acid conversion. These observations indicate the presence of an allosteric binding site in human 5-LOX distinct from the ATP binding site. The activatory and inhibitory behavior of 23a and 23d on the conversion of linoleic compared to arachidonic acid are rationalized by docking studies, which suggest that the activator 23a stabilizes linoleic acid, whereas the larger inhibitor 23d blocks the enzyme active site.

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Micelle and acid-soap formation of linoleic acid and 13-L-hydroperoxylinoleic acid being substrates of lipoxygenase-1

Cited by 49 publications

References 10 publications

Secreted Fungal Effector Lipase Releases Free Fatty Acids to Inhibit Innate Immunity-Related Callose Formation during Wheat Head Infection

Secreted Fungal Effector Lipase Releases Free Fatty Acids to Inhibit Innate Immunity-Related Callose Formation during Wheat Head Infection

The Dioxygenation Rate In Lipoxygenase Catalysis Is Determined by the Amount of Iron(III) Lipoxygenase in Solution

Discovery of a novel activator of 5-lipoxygenase from an anacardic acid derived compound collection

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