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A lipoxygenase from red alga Pyropia haitanensis, a unique enzyme catalyzing the free radical reactions of polyunsaturated fatty acids with triple ethylenic bonds.

Zhu Z, Qian F, Yang R, Chen J, Luo Q, Chen H, Yan X - PLoS ONE (2015)

Bottom Line: It was found that at least triple ethylenic bonds are required for PhLOX2 to function as a LOX, and the resulting hydroxy products should be originated from the PhLOX2 mediated reduction of mono-hydroperoxides, in which the hydrogen abstraction occurs on the carbon atom between the second and third double bond.Most of the di-hydroperoxides observed seem to be missing their mono-position precursors.The substrate and position flexibility, as well as the function versatility of PhLOXs represent the ancient enzymatic pathway for organisms to control intracellular oxylipins.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Applied Marine Biotechnology, Ningbo University, Ningbo, Zhejiang, 315211, China.

ABSTRACT
Lipoxygenases (LOXs) are key enzymes to regulate the production of hormones and defensive metabolites in plants, animals and algae. In this research, a full length LOX gene has been cloned and expressed from the red alga Pyropia haitanensis (Bangiales, Rhodophyta) gametophyte (PhLOX2). Subsequent phylogenetic analysis showed that such LOX enzymes are separated at the early stage of evolution, establishing an independent branch. The LOX activity was investigated at the optimal pH of 8.0. It appears that PhLOX2 is a multifunctional enzyme featuring both lipoxygenase and hydroperoxidase activities. Additionally, PhLOX2 exhibits remarkable substrate and position flexibility, and it can catalyze an array of chemical reactions involving various polyunsaturated fatty acids, ranging from C18 to C22. As a matter of fact, mono-hydroperoxy, di-hydroperoxy and hydroxyl products have been obtained from such transformations, and eicosapentaenoic acid seem to be the most preferred substrate. It was found that at least triple ethylenic bonds are required for PhLOX2 to function as a LOX, and the resulting hydroxy products should be originated from the PhLOX2 mediated reduction of mono-hydroperoxides, in which the hydrogen abstraction occurs on the carbon atom between the second and third double bond. Most of the di-hydroperoxides observed seem to be missing their mono-position precursors. The substrate and position flexibility, as well as the function versatility of PhLOXs represent the ancient enzymatic pathway for organisms to control intracellular oxylipins.

No MeSH data available.


Related in: MedlinePlus

LC-MS analysis for the catalytic reaction of EPA with PhLOX2.(I), (II) and (III) showed the mass spectra and the corresponding MS/MS fragmentation scheme of 8-HpEPE, 8-HEPE and 9,12-diHpEPA, respectively.
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pone.0117351.g006: LC-MS analysis for the catalytic reaction of EPA with PhLOX2.(I), (II) and (III) showed the mass spectra and the corresponding MS/MS fragmentation scheme of 8-HpEPE, 8-HEPE and 9,12-diHpEPA, respectively.

Mentions: The catalytic activity of PhLOX2 against LA, ALA, GLA, AA, EPA and DHA has been closely examined with the assistance of LC and high resolution mass spectrometry analyses, as shown in Table 2. We found that PhLOX2 showed no activity to LA and ALA. Fig. 6 listed the LC and high resolution MS/MS spectra of different types of products (mono-, di-hydroperoxy and hydroxyl compounds) from the PhLOX2 catalyzed reactions of EPA. In the MS spectrum, [M-H]- ions at m/z 315.1974, 317.2129 and 365.1977 for 8-HpEPE, 8-HEPE and 9, 12-diHpEPE were all observed. Besides, the proposed fragmentation pathways were also included.


A lipoxygenase from red alga Pyropia haitanensis, a unique enzyme catalyzing the free radical reactions of polyunsaturated fatty acids with triple ethylenic bonds.

Zhu Z, Qian F, Yang R, Chen J, Luo Q, Chen H, Yan X - PLoS ONE (2015)

LC-MS analysis for the catalytic reaction of EPA with PhLOX2.(I), (II) and (III) showed the mass spectra and the corresponding MS/MS fragmentation scheme of 8-HpEPE, 8-HEPE and 9,12-diHpEPA, respectively.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4319731&req=5

pone.0117351.g006: LC-MS analysis for the catalytic reaction of EPA with PhLOX2.(I), (II) and (III) showed the mass spectra and the corresponding MS/MS fragmentation scheme of 8-HpEPE, 8-HEPE and 9,12-diHpEPA, respectively.
Mentions: The catalytic activity of PhLOX2 against LA, ALA, GLA, AA, EPA and DHA has been closely examined with the assistance of LC and high resolution mass spectrometry analyses, as shown in Table 2. We found that PhLOX2 showed no activity to LA and ALA. Fig. 6 listed the LC and high resolution MS/MS spectra of different types of products (mono-, di-hydroperoxy and hydroxyl compounds) from the PhLOX2 catalyzed reactions of EPA. In the MS spectrum, [M-H]- ions at m/z 315.1974, 317.2129 and 365.1977 for 8-HpEPE, 8-HEPE and 9, 12-diHpEPE were all observed. Besides, the proposed fragmentation pathways were also included.

Bottom Line: It was found that at least triple ethylenic bonds are required for PhLOX2 to function as a LOX, and the resulting hydroxy products should be originated from the PhLOX2 mediated reduction of mono-hydroperoxides, in which the hydrogen abstraction occurs on the carbon atom between the second and third double bond.Most of the di-hydroperoxides observed seem to be missing their mono-position precursors.The substrate and position flexibility, as well as the function versatility of PhLOXs represent the ancient enzymatic pathway for organisms to control intracellular oxylipins.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Applied Marine Biotechnology, Ningbo University, Ningbo, Zhejiang, 315211, China.

ABSTRACT
Lipoxygenases (LOXs) are key enzymes to regulate the production of hormones and defensive metabolites in plants, animals and algae. In this research, a full length LOX gene has been cloned and expressed from the red alga Pyropia haitanensis (Bangiales, Rhodophyta) gametophyte (PhLOX2). Subsequent phylogenetic analysis showed that such LOX enzymes are separated at the early stage of evolution, establishing an independent branch. The LOX activity was investigated at the optimal pH of 8.0. It appears that PhLOX2 is a multifunctional enzyme featuring both lipoxygenase and hydroperoxidase activities. Additionally, PhLOX2 exhibits remarkable substrate and position flexibility, and it can catalyze an array of chemical reactions involving various polyunsaturated fatty acids, ranging from C18 to C22. As a matter of fact, mono-hydroperoxy, di-hydroperoxy and hydroxyl products have been obtained from such transformations, and eicosapentaenoic acid seem to be the most preferred substrate. It was found that at least triple ethylenic bonds are required for PhLOX2 to function as a LOX, and the resulting hydroxy products should be originated from the PhLOX2 mediated reduction of mono-hydroperoxides, in which the hydrogen abstraction occurs on the carbon atom between the second and third double bond. Most of the di-hydroperoxides observed seem to be missing their mono-position precursors. The substrate and position flexibility, as well as the function versatility of PhLOXs represent the ancient enzymatic pathway for organisms to control intracellular oxylipins.

No MeSH data available.


Related in: MedlinePlus