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Noguchi S, Tallman KA, Porter NA, Stec DF, Calcutt MW, Boeglin WE, Brash AR. Evaluation of ω-alkynyl-labeled linoleic and arachidonic acids as substrates for recombinant lipoxygenase pathway enzymes. Biochim Biophys Acta Mol Cell Biol Lipids 2023; 1868:159360. [PMID: 37336389 PMCID: PMC10528070 DOI: 10.1016/j.bbalip.2023.159360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 06/02/2023] [Accepted: 06/11/2023] [Indexed: 06/21/2023]
Abstract
ω-Alkynyl-fatty acids can be used as probes for covalent binding to intracellular macromolecules. To inform future in vivo studies, we determined the rates of reaction of ω-alkynyl-labeled linoleate with recombinant enzymes of the skin 12R-lipoxygenase (12R-LOX) pathway involved in epidermal barrier formation (12R-LOX, epidermal lipoxygenase-3 (eLOX3), and SDR9C7). We also examined the reactivity of ω-alkynyl-arachidonic acid with representative lipoxygenase enzymes employing either "carboxyl end-first" substrate binding (5S-LOX) or "tail-first" (platelet-type 12S-LOX). ω-Alkynyl-linoleic acid was oxygenated by 12R-LOX at 62 ± 9 % of the rate compared to linoleic acid, the alkynyl-9R-HPODE product was isomerized by eLOX3 at only 43 ± 1 % of the natural substrate, whereas its epoxy alcohol product was converted to epoxy ketone linoleic by an NADH-dependent dehydrogenase (SDR9C7) with 91 ± 1 % efficiency. The results suggest the optimal approach will be application of the 12R-LOX/eLOX3-derived epoxyalcohol, which should be most efficiently incorporated into the pathway and allow subsequent analysis of covalent binding to epidermal proteins. Regarding the orientation of substrate binding in LOX catalysis, our results and previous reports suggest the ω-alkynyl group has a stronger inhibitory effect on tail-first binding, as might be expected. Beyond slowing the reaction, however, we found that the tail-first binding and transformation of ω-alkynyl-arachidonic acid by platelet-type 12S-LOX results in almost complete enzyme inactivation, possibly due to reactive intermediates blocking the enzyme active site. Overall, the results reinforce the conclusion that ω-alkynyl-fatty acids are suitable for selected applications after appropriate reactivity is established.
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Affiliation(s)
- Saori Noguchi
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232, United States of America
| | - Keri A Tallman
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, United States of America
| | - Ned A Porter
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, United States of America
| | - Donald F Stec
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, United States of America
| | - M Wade Calcutt
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, United States of America
| | - William E Boeglin
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232, United States of America
| | - Alan R Brash
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232, United States of America.
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2
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Benatzy Y, Palmer MA, Brüne B. Arachidonate 15-lipoxygenase type B: Regulation, function, and its role in pathophysiology. Front Pharmacol 2022; 13:1042420. [PMID: 36438817 PMCID: PMC9682198 DOI: 10.3389/fphar.2022.1042420] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 10/26/2022] [Indexed: 10/30/2023] Open
Abstract
As a lipoxygenase (LOX), arachidonate 15-lipoxygenase type B (ALOX15B) peroxidizes polyenoic fatty acids (PUFAs) including arachidonic acid (AA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and linoleic acid (LA) to their corresponding fatty acid hydroperoxides. Distinctive to ALOX15B, fatty acid oxygenation occurs with positional specificity, catalyzed by the non-heme iron containing active site, and in addition to free PUFAs, membrane-esterified fatty acids serve as substrates for ALOX15B. Like other LOX enzymes, ALOX15B is linked to the formation of specialized pro-resolving lipid mediators (SPMs), and altered expression is apparent in various inflammatory diseases such as asthma, psoriasis, and atherosclerosis. In primary human macrophages, ALOX15B expression is associated with cellular cholesterol homeostasis and is induced by hypoxia. Like in inflammation, the role of ALOX15B in cancer is inconclusive. In prostate and breast carcinomas, ALOX15B is attributed a tumor-suppressive role, whereas in colorectal cancer, ALOX15B expression is associated with a poorer prognosis. As the biological function of ALOX15B remains an open question, this review aims to provide a comprehensive overview of the current state of research related to ALOX15B.
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Affiliation(s)
- Yvonne Benatzy
- Faculty of Medicine, Institute of Biochemistry I, Goethe University Frankfurt, Frankfurt, Germany
| | - Megan A. Palmer
- Faculty of Medicine, Institute of Biochemistry I, Goethe University Frankfurt, Frankfurt, Germany
| | - Bernhard Brüne
- Faculty of Medicine, Institute of Biochemistry I, Goethe University Frankfurt, Frankfurt, Germany
- Frankfurt Cancer Institute, Goethe University Frankfurt, Frankfurt, Germany
- German Cancer Consortium (DKTK), Partner Site Frankfurt, Frankfurt, Germany
- Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, Frankfurt, Germany
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3
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Activity of sEH and Oxidant Status during Systemic Bovine Coliform Mastitis. Antioxidants (Basel) 2021; 10:antiox10050812. [PMID: 34065244 PMCID: PMC8161397 DOI: 10.3390/antiox10050812] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 05/14/2021] [Accepted: 05/15/2021] [Indexed: 12/31/2022] Open
Abstract
Bovine coliform mastitis presents treatment challenges because of systemic inflammation and oxidative stress. Soluble epoxide hydrolase (sEH) is a promising therapeutic target in conditions characterized by inflammation and oxidative stress but has not been evaluated in cattle. We compared sEH activity and oxidant status in healthy Holstein dairy cows to those with systemic coliform mastitis (n = 5/group) using complementary approaches. First, the activity of sEH on [3H]-trans-diphenyl-propene oxide (tDPPO) was assessed ex vivo using tissue homogenates (mammary, liver, and kidney). Second, the concentrations of sEH substrates and metabolites in plasma, milk, and urine were determined as an index of in vivo sEH activity. Oxidant status was assessed in serum and milk. Data were analyzed by non-parametric methods. Metabolism of tDPPO was greater in mammary tissues from cows with coliform mastitis compared to controls. In contrast, ratios of sEH substrates and metabolites predicted lower sEH activity in cows with coliform mastitis than controls. Milk oxidant status showed greater prooxidant levels in coliform mastitis cows. Cows with coliform mastitis exhibit increased sEH activity in mammary tissue; at the same time, milk oxidant status is increased. Future studies should characterize sEH activity and oxidant status patterns and explore therapies targeting sEH during coliform mastitis.
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4
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Song JW, Seo JH, Oh DK, Bornscheuer UT, Park JB. Design and engineering of whole-cell biocatalytic cascades for the valorization of fatty acids. Catal Sci Technol 2020. [DOI: 10.1039/c9cy01802f] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
This review presents the key factors to construct a productive whole-cell biocatalytic cascade exemplified for the biotransformation of renewable fatty acids.
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Affiliation(s)
- Ji-Won Song
- Department of Food Science and Engineering
- Ewha Womans University
- Seoul 03760
- Republic of Korea
| | - Joo-Hyun Seo
- Department of Bio and Fermentation Convergence Technology
- Kookmin University
- Seoul 02707
- Republic of Korea
| | - Doek-Kun Oh
- Department of Bioscience and Biotechnology
- Konkuk University
- Seoul 143-701
- Republic of Korea
| | - Uwe T. Bornscheuer
- Institute of Biochemistry
- Department of Biotechnology & Enzyme Catalysis
- Greifswald University
- 17487 Greifswald
- Germany
| | - Jin-Byung Park
- Department of Food Science and Engineering
- Ewha Womans University
- Seoul 03760
- Republic of Korea
- Institute of Molecular Microbiology and Biosystems Engineering
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5
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Hajeyah AA, Griffiths WJ, Wang Y, Finch AJ, O’Donnell VB. The Biosynthesis of Enzymatically Oxidized Lipids. Front Endocrinol (Lausanne) 2020; 11:591819. [PMID: 33329396 PMCID: PMC7711093 DOI: 10.3389/fendo.2020.591819] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 10/26/2020] [Indexed: 12/14/2022] Open
Abstract
Enzymatically oxidized lipids are a specific group of biomolecules that function as key signaling mediators and hormones, regulating various cellular and physiological processes from metabolism and cell death to inflammation and the immune response. They are broadly categorized as either polyunsaturated fatty acid (PUFA) containing (free acid oxygenated PUFA "oxylipins", endocannabinoids, oxidized phospholipids) or cholesterol derivatives (oxysterols, steroid hormones, and bile acids). Their biosynthesis is accomplished by families of enzymes that include lipoxygenases (LOX), cyclooxygenases (COX), cytochrome P450s (CYP), and aldo-keto reductases (AKR). In contrast, non-enzymatically oxidized lipids are produced by uncontrolled oxidation and are broadly considered to be harmful. Here, we provide an overview of the biochemistry and enzymology of LOXs, COXs, CYPs, and AKRs in humans. Next, we present biosynthetic pathways for oxylipins, oxidized phospholipids, oxysterols, bile acids and steroid hormones. Last, we address gaps in knowledge and suggest directions for future work.
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Affiliation(s)
- Ali A. Hajeyah
- Systems Immunity Research Institute and Division of Infection and Immunity, Cardiff University, Cardiff, United Kingdom
- *Correspondence: Ali A. Hajeyah,
| | - William J. Griffiths
- Institute of Life Science, Swansea University Medical School, Swansea, United Kingdom
| | - Yuqin Wang
- Institute of Life Science, Swansea University Medical School, Swansea, United Kingdom
| | - Andrew J. Finch
- Centre for Tumour Biology, Barts Cancer Institute, Queen Mary University of London, London, United Kingdom
| | - Valerie B. O’Donnell
- Systems Immunity Research Institute and Division of Infection and Immunity, Cardiff University, Cardiff, United Kingdom
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Involvement of the Hydroperoxy Group in the Irreversible Inhibition of Leukocyte-Type 12-Lipoxygenase by Monoterpene Glycosides Contained in the Qing Shan Lu Shui Tea. Molecules 2019; 24:molecules24020304. [PMID: 30650646 PMCID: PMC6358863 DOI: 10.3390/molecules24020304] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Revised: 01/08/2019] [Accepted: 01/14/2019] [Indexed: 11/21/2022] Open
Abstract
We have previously found two novel monoterpene glycosides, liguroside A and liguroside B, with an inhibitory effect on the catalytic activity of the enzyme leukocyte-type 12-lipoxygenase in the Qing Shan Lu Shui tea. Here, two new monoterpene glycosides, liguroside C and liguroside D which inhibit this enzyme, were isolated from the same tea. The spectral and chemical evidence characterized the structures of these compounds as (5E)-7-hydroperoxy-3,7-dimethyl-1,5-octadienyl-3-O-(α-l-rhamnopyranosyl)-(1′′→3′)-(4′′′-O-trans-p-coumaroyl)-β-d-glucopyranoside and (2E)-6-hydroxy-3,7-dimethyl-2,7-octadienyl-3-O-(α-l-rhamnopyranosyl)-(1′′→3′)-(4′′′-O-trans-p-coumaroyl)-β-d-glucopyranoside, respectively. These ligurosides, which irreversibly inhibited leukocyte-type 12-lipoxygenase, have a hydroperoxy group in the monoterpene moiety. Additionally, monoterpene glycosides had the same backbone structure but did not have a hydroperoxy group, such as kudingoside A and lipedoside B-III, contained in the tea did not inhibit the enzyme. When a hydroperoxy group in liguroside A was reduced by using triphenylphosphine, the resultant compound, kudingoside B, showed a lower inhibitory effect on the enzyme. These results strongly suggest the involvement of the hydroperoxy group in the irreversible inhibition of the catalytic activity of leukocyte-type 12-lipoxygenase by the monoterpene glycosides contained in the Qing Shan Lu Shui tea.
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7
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Meng H, Dai Z, Zhang W, Liu Y, Lai L. Molecular mechanism of 15-lipoxygenase allosteric activation and inhibition. Phys Chem Chem Phys 2018; 20:14785-14795. [PMID: 29780994 DOI: 10.1039/c7cp08586a] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Human reticulocyte 15-lipoxygenase (15-LOX) plays an important role in inflammation resolution and is also involved in many cancer-related processes. Both an activator and an inhibitor will serve as research tools for understanding the biological functions of 15-LOX and provide opportunities for drug discovery. In a previous study, both allosteric activators and inhibitors of 15-LOX were discovered through a virtual screening based computational approach. However, why molecules binding to the same site causes different effects remains to be disclosed. In the present study, we used previously reported activator and inhibitor molecules as probes to elucidate the mechanism of allosteric regulation of 15-LOX. We measured the influences of the allosteric activator and inhibitor on the enzymatic reaction rate and found that the activator increases 15-LOX activity by preventing substrate inhibition instead of increasing the turnover number. The inhibitor can also prevent substrate inhibition but decreases the turnover number at the same time, resulting in inhibition. Molecular dynamics simulations were conducted to help explain the underlying mechanism of allostery. Both the activator and inhibitor were demonstrated to be able to prevent 15-LOX from transforming into potentially inactive conformations. Compared to the activator, the inhibitor molecule restrains the motions of residues around the substrate binding site and reduces the flexibility of 15-LOX. These results explained the different effects between the activator and the inhibitor and shed light on how to effectively design novel activator molecules.
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Affiliation(s)
- Hu Meng
- BNLMS, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, College of Chemistry and Molecular Engineering, Peking University, A518 Chemistry Building, 202 Chengfu Road, Beijing 100871, China.
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8
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Isobe Y, Kawashima Y, Ishihara T, Watanabe K, Ohara O, Arita M. Identification of Protein Targets of 12/15-Lipoxygenase-Derived Lipid Electrophiles in Mouse Peritoneal Macrophages Using Omega-Alkynyl Fatty Acid. ACS Chem Biol 2018; 13:887-893. [PMID: 29461797 DOI: 10.1021/acschembio.7b01092] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The 12/15-lipoxygenase (12/15-LOX) enzyme introduces peroxyl groups, in a position-specific manner, into polyunsaturated fatty acids to form various kinds of bioactive lipid metabolites, including lipid-derived electrophiles (LDE). The resident peritoneal macrophage is the site of highest 12/15-LOX expression in the mouse. However, the role of the enzyme in the regulation of resident macrophages is not fully understood. Here, we describe a chemoproteomic method to identify the targets of enzymatically generated LDE. By treating mouse peritoneal macrophages with omega-alkynyl arachidonic acid (aAA), we identified a series of proteins adducted by LDE generated through a 12/15-LOX catalyzed reaction. Pathway analysis revealed a dramatic enrichment of proteins involved in energy metabolism and found that glycolytic flux and mitochondrial respiration were significantly affected by the expression of 12/15-LOX. Our findings thus highlight the utility of chemoproteomics using aAA for identifying intracellular targets of enzymatically generated LDE.
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Affiliation(s)
- Yosuke Isobe
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29, Suehiro-cho, Tsurumi, Yokohama, Kanagawa 230-0045, Japan
| | | | - Tomoaki Ishihara
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29, Suehiro-cho, Tsurumi, Yokohama, Kanagawa 230-0045, Japan
| | - Kenji Watanabe
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29, Suehiro-cho, Tsurumi, Yokohama, Kanagawa 230-0045, Japan
| | | | - Makoto Arita
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29, Suehiro-cho, Tsurumi, Yokohama, Kanagawa 230-0045, Japan
- Division of Physiological Chemistry and Metabolism, Keio University Faculty of Pharmacy, 1-5-30, Shibakoen, Minato-ku, Tokyo, 105-0011, Japan
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9
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Umeno A, Morita M, Yoshida Y, Naito Y, Niki E. Isomer distribution of hydroxyoctadecadienoates (HODE) and hydroxyeicosatetraenoates (HETE) produced in the plasma oxidation mediated by peroxyl radical, peroxynitrite, hypochlorite, 15-lipoxygenase, and singlet oxygen. Arch Biochem Biophys 2017; 635:96-101. [DOI: 10.1016/j.abb.2017.10.023] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 10/25/2017] [Accepted: 10/29/2017] [Indexed: 12/14/2022]
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10
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Ahanger MA, Tomar NS, Tittal M, Argal S, Agarwal RM. Plant growth under water/salt stress: ROS production; antioxidants and significance of added potassium under such conditions. PHYSIOLOGY AND MOLECULAR BIOLOGY OF PLANTS : AN INTERNATIONAL JOURNAL OF FUNCTIONAL PLANT BIOLOGY 2017; 23:731-744. [PMID: 29158624 PMCID: PMC5671444 DOI: 10.1007/s12298-017-0462-7] [Citation(s) in RCA: 161] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2017] [Accepted: 07/31/2017] [Indexed: 05/18/2023]
Abstract
Plants are confronted with a variety of environmenmtal stresses resulting in enhanced production of ROS. Plants require a threshold level of ROS for vital functions and any change in their concentration alters the entire physiology of plant. Delicate balance of ROS is maintained by an efficient functioning of intriguing indigenous defence system called antioxidant system comprising enzymatic and non enzymatic components. Down regulation of antioxidant system leads to ROS induced oxidative stress causing damage to important cellular structures and hence anomalies in metabolism. Proper mineral nutrition, in addition to other agricultural practices, forms an important part for growth and hence the yield. Potassium (K) is a key macro-element regulating growth and development through alterations in physiological and biochemical attributes. K has been reported to result into accumulation of osmolytes and augmentation of antioxidant components in the plants exposed to water and salt stress. In the present review an effort has been made to revisit the old findings and the current advances in research regarding the role of optimal, suboptimal and deficient K soil status on growth under normal and stressful conditions. Effect of K deficiency and sufficiency is discussed and the information about the K mediated antioxidant regulation and plant response is highlighted.
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Affiliation(s)
| | - Nisha Singh Tomar
- School of Studies in Botany, Jiwaji University, Gwalior, MP 474011 India
| | - Megha Tittal
- School of Studies in Botany, Jiwaji University, Gwalior, MP 474011 India
| | - Surendra Argal
- School of Studies in Botany, Jiwaji University, Gwalior, MP 474011 India
| | - R. M. Agarwal
- School of Studies in Botany, Jiwaji University, Gwalior, MP 474011 India
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11
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Ryman V, Packiriswamy N, Norby B, Schmidt S, Lock A, Sordillo L. Supplementation of linoleic acid (C18:2n-6) or α-linolenic acid (C18:3n-3) changes microbial agonist-induced oxylipid biosynthesis. J Dairy Sci 2017; 100:1870-1887. [DOI: 10.3168/jds.2016-11599] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 11/18/2016] [Indexed: 12/25/2022]
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12
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Zhang Y, Tang J, Zhao J, Wu H, Ditta YA, Zhang J. The Interaction Between Lipoxygenase-Catalyzed Oxidation and Autoxidation in Dry-Cured Bacon and a Model System. J Food Sci 2015; 80:C2640-6. [PMID: 26523477 DOI: 10.1111/1750-3841.13100] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Accepted: 09/06/2015] [Indexed: 11/30/2022]
Abstract
A model system was conducted to characterize the interaction between lipid autoxidation and enzyme-catalyzed oxidation in dry-cured bacon. This involved the use of a hydroxyl radical (HO•) generating system and the extraction and purification of lipoxygenases (LOX) from pork belly. The results showed that LOX activity rapidly (P < 0.05) increased during the curing of dry-cured bacon. This may be because of the hydroxyl-radical-mediated oxidation from LOX-Fe(2+) to LOX-Fe(3+), which activates LOX. In addition, experiments of the model system also showed that LOX activity could be inhibited by increasing the substrate concentration, although substrate type and concentration had no effect on autoxidation. Moreover, LOX enzyme-catalyzed oxidation and autoxidation could act synergistically to promote lipid oxidation irrespective of the substrate (linoleic or arachidonic acid). These results provide useful information for regulating lipid oxidation during the production of dry-cured pork products.
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Affiliation(s)
- Yingyang Zhang
- College of Food Science and Technology, Nanjing Agricultural Univ, Nanjing, 210095, P. R. China.,Dept. of Animal Science, Univ. of California, Davis, CA, 95616, U.S.A
| | - Jing Tang
- College of Food Science and Technology, Nanjing Agricultural Univ, Nanjing, 210095, P. R. China
| | - Jianying Zhao
- College of Food Science and Technology, Nanjing Agricultural Univ, Nanjing, 210095, P. R. China
| | - Haizhou Wu
- College of Food Science and Technology, Nanjing Agricultural Univ, Nanjing, 210095, P. R. China
| | - Yasir Allah Ditta
- Dept. of Animal Nutrition, Univ. of Veterinary and Animal Sciences, Lahore, Punjab, Pakistan
| | - Jianhao Zhang
- College of Food Science and Technology, Nanjing Agricultural Univ, Nanjing, 210095, P. R. China
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Abstract
Lipoxygenases (LOX) form a family of lipid peroxidizing enzymes, which have been implicated in a number of physiological processes and in the pathogenesis of inflammatory, hyperproliferative and neurodegenerative diseases. They occur in two of the three domains of terrestrial life (bacteria, eucarya) and the human genome involves six functional LOX genes, which encode for six different LOX isoforms. One of these isoforms is ALOX15, which has first been described in rabbits in 1974 as enzyme capable of oxidizing membrane phospholipids during the maturational breakdown of mitochondria in immature red blood cells. During the following decades ALOX15 has extensively been characterized and its biological functions have been studied in a number of cellular in vitro systems as well as in various whole animal disease models. This review is aimed at summarizing the current knowledge on the protein-chemical, molecular biological and enzymatic properties of ALOX15 in various species (human, mouse, rabbit, rat) as well as its implication in cellular physiology and in the pathogenesis of various diseases.
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Affiliation(s)
- Igor Ivanov
- Institute of Biochemistry, Charité - University Medicine Berlin, Charitéplatz 1, CCO-Building, Virchowweg 6, D-10117 Berlin, Germany
| | - Hartmut Kuhn
- Institute of Biochemistry, Charité - University Medicine Berlin, Charitéplatz 1, CCO-Building, Virchowweg 6, D-10117 Berlin, Germany.
| | - Dagmar Heydeck
- Institute of Biochemistry, Charité - University Medicine Berlin, Charitéplatz 1, CCO-Building, Virchowweg 6, D-10117 Berlin, Germany
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14
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Ivanov I, Shang W, Toledo L, Masgrau L, Svergun DI, Stehling S, Gómez H, Di Venere A, Mei G, Lluch JM, Skrzypczak-Jankun E, González-Lafont A, Kühn H. Ligand-induced formation of transient dimers of mammalian 12/15-lipoxygenase: a key to allosteric behavior of this class of enzymes? Proteins 2011; 80:703-12. [PMID: 22189720 DOI: 10.1002/prot.23227] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2011] [Revised: 10/03/2011] [Accepted: 10/10/2011] [Indexed: 02/02/2023]
Abstract
Mammalian lipoxygenases (LOXs) have been implicated in cellular defense response and are important for physiological homeostasis. Since their discovery, LOXs have been believed to function as monomeric enzymes that exhibit allosteric properties. In aqueous solutions, the rabbit 12/15-LOX is mainly present as hydrated monomer but changes in the local physiochemical environment suggested a monomer-dimer equilibrium. Because the allosteric character of the enzyme can hardly be explained using a single ligand binding-site model, we proposed that the binding of allosteric effectors may shift the monomer-dimer equilibrium toward dimer formation. To test this hypothesis, we explored the impact of an allosteric effector [13(S)-hydroxyoctadeca-9(Z),11(E)-dienoic acid] on the structural properties of rabbit 12/15-LOX by small-angle X-ray scattering. Our data indicate that the enzyme undergoes ligand-induced dimerization in aqueous solution, and molecular dynamics simulations suggested that LOX dimers may be stable in the presence of substrate fatty acids. These data provide direct structural evidence for the existence of LOX dimers, where two noncovalently linked enzyme molecules might work in unison and, therefore, such mode of association might be related to the allosteric character of 12/15-LOX. Introduction of negatively charged residues (W181E + H585E and L183E + L192E) at the intermonomer interface disturbs the hydrophobic dimer interaction of the wild-type LOX, and this structural alteration may lead to functional distortion of mutant enzymes.
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Affiliation(s)
- Igor Ivanov
- Institute of Biochemistry, Charité-Universitätsmedizin Berlin, D-13346 Berlin, Germany.
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15
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Kuhn H, Saam J, Eibach S, Holzhütter HG, Ivanov I, Walther M. Structural biology of mammalian lipoxygenases: Enzymatic consequences of targeted alterations of the protein structure. Biochem Biophys Res Commun 2005; 338:93-101. [PMID: 16168952 DOI: 10.1016/j.bbrc.2005.08.238] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2005] [Accepted: 08/27/2005] [Indexed: 11/19/2022]
Abstract
Lipoxygenases form a heterogeneous family of lipid peroxidizing enzymes, which have been implicated in the pathogenesis of diseases with major health political relevance (bronchial asthma, atherosclerosis, cancer, and osteoporosis). The crystal structures of one mammalian lipoxygenase and of two plant isoenzymes have been solved and the structural bases of important enzyme properties (reaction specificity, membrane binding, and suicidal inactivation) have been investigated in the past. This review will briefly summarize our current understanding on the structural biology of the most important mammalian lipoxygenase isoforms and will also address selected mechanistic features of the lipoxygenase reaction.
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Affiliation(s)
- Hartmut Kuhn
- Institute of Biochemistry, University Medicine Berlin-Charite, Monbijoustr. 2, 10117 Berlin, Germany.
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16
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Szczeklik A, Sanak M, Nizankowska-Mogilnicka E, Kiełbasa B. Aspirin intolerance and the cyclooxygenase-leukotriene pathways. Curr Opin Pulm Med 2004; 10:51-6. [PMID: 14749606 DOI: 10.1097/00063198-200401000-00009] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW In up to 10% of patients with bronchial asthma, aspirin and other nonsteroidal antiinflammatory drugs precipitate asthmatic attacks. This is a hallmark of a distinct clinical syndrome that develops according to a characteristic sequence of symptoms. Here we discuss its clinical picture and management as related to the abnormalities in arachidonic acid transformations. RECENT FINDINGS At the biochemical level, the characteristic feature is profound alteration in eicosanoid biosynthesis and metabolism. Major advances in the molecular biology of eicosanoids, exemplified by the cloning of cysteinyl-leukotriene receptors and discovery of a whole family of cyclooxygenase enzymes, offer new insights into mechanisms operating in aspirin-induced asthma. Clinical interest has been enhanced by the introduction into therapy of highly specific cyclooxygenase-2 inhibitors and antileukotriene drugs. SUMMARY Recent studies have improved our understanding of mechanisms operating in asthma and unvieled the role of eicosanoid mediators in pulmonary disease.
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Affiliation(s)
- Andrew Szczeklik
- Department of Medicine, Jagiellonian University School of Medicine, Kraków, Poland.
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