Demonstration by EPR spectroscopy of the functional role of iron in soybean lipoxygenase-1

Groot, J.J.M.C. de; Veldink, Gerrit A.; Vliegenthart, Johannes F.G.; Boldingh, J.; Wever, R.; Gelder, B.F. Van

doi:10.1016/0005-2744(75)90287-9

Cited by 311 publications

(167 citation statements)

References 18 publications

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“…It is likely that the lipohydroperoxidase activity is involved in the inactivation of reticulocyte lipoxygenase by 13-hydroperoxylinoleic acid as a suicidal step. The immediate attack may be caused by an intermediate of the lipohydroperoxidase reaction such as the oxylinoleic acid radical, the occurrence of which has been postulated for the same reaction catalyzed by soybean lipoxygenase [13]. In favour of a participation of the lipohydroperoxidase reaction is the accelerated inactivation in the presence of IinoIeic acid (Fig.…”

Section: Discussionmentioning

confidence: 81%

“…From the absorbance changes in the experiment in Fig.4A it was calculated that the product mixture consisted of about 35 oxodienes, 26 "/, non-hydroperoxide diene, presumably 13-hydroxylinoleic acid and 38 compounds not absorbing in the ultraviolet region, possibly epoxyhydroxy compounds. The rate of the total anaerobic lipohydroperoxidase activity in the presence of linoleic acid amounted to about one fifth of the corresponding aerobic linoleic acid oxy- 13-hydroperoxylinoleic acid were preincubated at 37 'C for the time indicated in the assay medium without linoleic acid (see Materials and Methods) previously made anaerobically. I0 p1 of preincubation sample were added to 1 nil of the aerobic spectrophotometric lipoxygenase assay at 2 "C. The control samples without 13-hydroperoxylinoleic acid showed no significant loss of activity during preincubation (not shown) ) and varying amounts of 13-hydroperoxylinoleic acid were preincubated at 37 :'C for 30 s in the assay medium without linoleic acid aerobically (0 --0) or anaerobically (A----A).…”

Section: Resultsmentioning

confidence: 99%

“…The concentration of oxodienes was calculated from the absorbance at 285 nm using an e of 2.2 x lo4 M-' cm-' [7]. 13-Hydroxylinoleic acid was obtained by reduction of 13-hydroperoxylinoleic acid by sodium borohydride in methanol at room temperature [8].…”

Section: Materials a N D Methodsmentioning

confidence: 99%

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Self‐Inactivation by 13‐Hydroperoxylinoleic Acid and Lipohydroperoxidase Activity of the Reticulocyte Lipoxygenase

Härtel

Ludwig

Schewe

et al. 1982

European Journal of Biochemistry

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1. The self-inactivation of lipoxygenase from rabbit reticulocytes with linoleic acid at 37 "C is caused by the product 13-hydroperoxylinoleic acid. This inactivation is promoted by either oxygen or linoleic acid.2. Lipohydroperoxidase activity was demonstrated with 13-hydroperoxylinoleic acid plus linoleic acid as hydrogen donor under anaerobic conditions at 2 "C. The products were 13-hydroxylinoleic acid, oxodienes and compounds of non-diene structure similar to those produced by soybean lipoxygenase-I .3. 13-Hydroperoxylinoleic acid also changed the absorbance and fluorescence properties of reticulocyte lipoxygenase. The results indicate that one equivalent of 13-hydroperoxylinoleic acid converts the enzyme from the ferrous state into the ferric state as described for soybean lipoxygenase-1. The spectral changes were reversed by sodium borohydride at 2 "C, but not at 37°C; it is assumed that the ferric form of reticulocyte lipoxygenase suffers inactivation.

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Section: Discussionmentioning

confidence: 81%

Section: Resultsmentioning

confidence: 99%

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Self‐Inactivation by 13‐Hydroperoxylinoleic Acid and Lipohydroperoxidase Activity of the Reticulocyte Lipoxygenase

Härtel

Ludwig

Schewe

et al. 1982

European Journal of Biochemistry

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“…The formation of 10% 13-HPODE (Fig. 4) within LOX1 biotransformation of linoleic acid could have resulted from the non-enzymatic peroxidation of the substrate linoleic acid during LOX1 catalysis as hypothesised by de Groot et al 3 The pentadienyl radical of the LOX cycle also reacts chemically with triplet oxygen to produce a racemic mixture of both regioisomers. Thus, the initial formation of the pentadienyl radical is catalysed by LOX and the term autoxidation does not describe this effect correctly.…”

Section: Stereoselectivity Of Partially Purified Lox Isoenzymesmentioning

confidence: 87%

“…13-HPODE, exhibited a racemic ratio indicating the complete absence of LOX2 in the IEF fraction used for biotransformation. The formation of racemic isomers within the LOX cycle has been discussed in the literature 3 .…”

Section: Stereoselectivity Of Partially Purified Lox Isoenzymesmentioning

confidence: 99%

Regio- and Stereoselectivity of Malt Lipoxygenases LOX1 and LOX2

Almeida

Garbe

Nagel

et al. 2005

Journal of the Institute of Brewing

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The characterisation of lipoxygenases LOX1 and LOX2 and hydroperoxyoctadecadienoic acid (HPODE) degrading enzymes from barley green malt is reported. Hydroxylapatite chromatography (HAC) and isoelectric focussing (IEF) were performed to separate and purify LOX isoenzymes. The regio-and stereoselectivity of LOX1 and LOX2 towards linoleic acid as substrate was characterised. HAC purified isoenzyme LOX1 showed a 9-HPODE:13-HPODE ratio of 75:25 and LOX2 a ratio of 39:61. IEF separated LOX1 and LOX2 transformed linoleic acid to 9-:13-HPODE ratios of 90:10, and 13:87, respectively. 9-HPODE stereoisomers from LOX1 exhibited a S:R ratio of 93:7 and 13-HPODE from LOX2 a S:R ratio of 89:11. However, the minor regioisomers were analysed with S:R = 48:52 (LOX1, 13-HPODE) and 40:60 (LOX2, 9-HPODE). These results indicate a complete LOX isoenzyme separation by IEF. Hydroperoxide-metabolising enzymes, which were investigated in the IEF fractions, did not interfere with the dual position specificities of LOX isoenzymes.

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Lipid Oxidation: Theoretical Aspects

Schaich

2005

Bailey's Industrial Oil and Fat Products

132

121

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Lipid oxidation has long been accepted as a classic free radical chain reaction mechanism with initiation, propagation, and termination stages. This view is not inaccurate, but it is incomplete. Initiation is generally treated as if it was spontaneous or random, but in reality, radical initiation is quite specific and varies with the source. Similarly, propagation is considered to involve only hydrogen abstraction where as internal cyclization, addition, scission, and disproportionation reactions are competitive or even dominant under some conditions, leading to variations in oxidation kinetics and, in particular, product mixes. Alternative reaction paths have been recognized for some time, but remain largely ignored in measurements of lipid oxidation. This chapter reviews initiation processes with a focus on differentiating rates, mechanisms, and specificity of radical formation; and it presents evidence for multiple propagation mechanisms that lead to different product mixes. Finally, a new integrated view of lipid oxidation is proposed to account for multiple propagation pathways. Practical application of this information should enable development of analyses that more accurately reflect the true extent of lipid oxidation and also antioxidant approaches that more effectively extend shelf life and preserve desirable food qualities.

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Demonstration by EPR spectroscopy of the functional role of iron in soybean lipoxygenase-1

Cited by 311 publications

References 18 publications

Self‐Inactivation by 13‐Hydroperoxylinoleic Acid and Lipohydroperoxidase Activity of the Reticulocyte Lipoxygenase

Self‐Inactivation by 13‐Hydroperoxylinoleic Acid and Lipohydroperoxidase Activity of the Reticulocyte Lipoxygenase

Regio- and Stereoselectivity of Malt Lipoxygenases LOX1 and LOX2

Lipid Oxidation: Theoretical Aspects

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