Iron Release from the Active Site of Lipoxygenase

Fuchs, Claus; Spiteller, Gerhard

doi:10.1515/znc-2000-7-825

Cited by 27 publications

(25 citation statements)

References 5 publications

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“…Iron release from lipoxygenase under non denaturing conditions is not unprecedented. It was recently reported that iron released from lipoxygenase during the catalyzed reaction could be captured as a complex with ferrozine (22). In our experiments, we found that removal of lipoxygenase iron by o-phenanthroline takes place readily in the presence of linoleic acid under anaerobic conditions.…”

Section: Discussionsupporting

confidence: 60%

Iron Extraction from Soybean Lipoxygenase 3 and Reconstitution of Catalytic Activity from the Apoenzyme

Kariapper

Dunham

Funk

2001

Biochemical and Biophysical Research Communications

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Section: Discussionsupporting

confidence: 60%

Iron Extraction from Soybean Lipoxygenase 3 and Reconstitution of Catalytic Activity from the Apoenzyme

Kariapper

Dunham

Funk

2001

Biochemical and Biophysical Research Communications

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“…However, recent experimental evidence strongly favors the fact that LOX mediated MLP processes often switch to a nonenzymatic MLP [139,148], when supply of substrates (PUFA) exceeds a certain limit, as evident in case of programmed cell death [149,150]. In fact, when supply of PUFA is significantly higher, it is found that LOX not only catalyzes MLP but also commits suicide by catalyzing the disintegration of its own molecule.…”

Section: •−mentioning

confidence: 99%

“…In fact, when supply of PUFA is significantly higher, it is found that LOX not only catalyzes MLP but also commits suicide by catalyzing the disintegration of its own molecule. This causes the release of enzyme bound Fe-ion [149,150], which subsequently reacts with the end product of LOX mediating MLP, that is, LOOH to produce LO…”

Section: •−mentioning

confidence: 99%

The Language of Reactive Oxygen Species Signaling in Plants

Bhattacharjee¹

2012

Journal of Botany

157

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Reactive oxygen species (ROS) are astonishingly versatile molecular species and radicals that are poised at the core of a sophisticated network of signaling pathways of plants and act as core regulator of cell physiology and cellular responses to environment. ROS are continuously generated in plants as an inevitable consequence of redox cascades of aerobic metabolism. In one hand, plants are surfeited with the mechanism to combat reactive oxygen species, in other circumstances, plants appear to purposefully generate (oxidative burst) and exploit ROS or ROS-induced secondary breakdown products for the regulation of almost every aspect of plant biology, from perception of environmental cues to gene expression. The molecular language associated with ROS-mediated signal transduction, leading to modulation in gene expression to be one of the specific early stress response in the acclamatory performance of the plant. They may even act as "second messenger" modulating the activities of specific proteins or expression of genes by changing redox balance of the cell. The network of redox signals orchestrates metabolism for regulating energy production to utilization, interfering with primary signaling agents (hormones) to respond to changing environmental cues at every stage of plant development. The oxidative lipid peroxidation products and the resulting generated products thereof (associated with stress and senescence) also represent "biological signals," which do not require preceding activation of genes. Unlike ROS-induced expression of genes, these lipid peroxidation products produce nonspecific response to a large variety of environmental stresses. The present review explores the specific and nonspecific signaling language of reactive oxygen species in plant acclamatory defense processes, controlled cell death, and development. Special emphasis is given to ROS and redox-regulated gene expression and the role of redox-sensitive proteins in signal transduction event. It also describes the emerging complexity of apparently contradictory roles that ROS play in cellular physiology to ascertain their position in the life of the plant.

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“…This limit concentration is always reached by severe cell-damaging reactions, such as homogenation. The self-deactivation is connected with the destruction of the shielding protein cover of the iron ions resulting in a partly liberation of the iron ions [36]. Liberation of iron ions was also observed to occur with mammalian 15-LOX after treatment with its products, LOOHs [37].…”

Section: Lpo Processes Are Involved In Cell Damagementioning

confidence: 98%

The relation of lipid peroxidation processes with atherogenesis: A new theory on atherogenesis

Spiteller¹

2005

Mol. Nutr. Food Res.

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The extremely high sensitivity of polyunsaturated fatty acids (PUFAs) to oxygen is apparently used by nature to induce stepwise appropriate cell responses. It is hypothesized that any alteration in the cell membrane structure induces influx of Ca2+ ions. Ca2+ ions are required to activate degrading enzymes, such as phospholipases and lipoxygenases (LOX) that transform PUFAs bound to membrane phospholipids to lipidhydroperoxides (LOOHs). Enzymatic reduction products of LOOHs seem to serve as ligands of proteins, which induce gene activation to initiate a physiological response. Increasing external impact on cells is connected with deactivation of LOX, liberation of the iron ion in its active center followed by cleavage of LOOH molecules to LO * radicals. LO * radicals induce a second set of responses leading to generation of unsaturated aldehydic phospholipids and unsaturated epoxyhydroxy acids that contribute to induction of apoptosis. Finally peroxyl radicals are generated by attack of LO * radicals on phospholipids. The latter attack nearly all types of cell constituents: Amino- and hydroxyl groups are oxidized to carbonyl functions, sugars and proteins are cleaved, molecules containing double bonds such as unsaturated fatty acids or cholesterol suffer epoxidation. LOOH molecules and iron ions at the cell wall of an injured cell are in tight contact with phospholipids of neighboring cells and transfer to these reactive radicals. Thus, the damaging processes proceed and cause finally necrosis except the chain reaction is stopped by scavengers, such as glutathione. Consequently, PUFAs incorporated into phospholipids of the cell wall are apparently equally important for the fate of a single organism as the DNA in the nucleus for conservation of the species. This review intends to demonstrate the connection of cell alteration reactions with induction of lipid peroxidation (LPO) processes and their relation to inflammatory diseases, especially atherosclerosis and a possible involvement of food. Previously it was deduced that food rich in cholesterol and saturated fatty acids is atherogenic, while food rich in n-3 PUFAs was recognized to be protective against vascular diseases. These deductions are in contradiction to the fact that saturated fatty acids withstand oxidation while n-3 PUFAs are subjected to LPO like all other PUFAs. Considering the influence of minor food constituents a new theory about atherogenesis and the influence of n-3 PUFAs is represented that might resolve the contradictory results of feeding experiments and chemical experiences. Cholesterol-PUFA esters are minor constituents of mammalian derived food, but main components of low density lipoprotein (LDL). The PUFA part of these esters occasionally suffers oxidation by heating or storage of mammalian derived food. There are indications that these oxidized cholesterol esters are directly incorporated into lipoproteins and transferred via the LDL into endothelial cells where they induce damage and start the sequence of events outlined above. The d...

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Iron Release from the Active Site of Lipoxygenase

Cited by 27 publications

References 5 publications

Iron Extraction from Soybean Lipoxygenase 3 and Reconstitution of Catalytic Activity from the Apoenzyme

Iron Extraction from Soybean Lipoxygenase 3 and Reconstitution of Catalytic Activity from the Apoenzyme

The Language of Reactive Oxygen Species Signaling in Plants

The relation of lipid peroxidation processes with atherogenesis: A new theory on atherogenesis

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