115185-06-3Relevant academic research and scientific papers
Stereospecific production of 9R-hydroxy-10E,12Z-octadecadienoic acid from linoleic acid by recombinant Escherichia coli cells expressing 9R-lipoxygenase from Nostoc sp. SAG 25.82
Kim, Kyoung-Rok,Seo, Min-Ho,Park, Jin-Byung,Oh, Deok-Kun
, p. 56 - 63 (2014/05/06)
One of the most significant properties of lipoxygenase (LOX) as a biocatalyst is its stereo-selective oxygenation. In this study, the stereo-specific production of 9R-hydroxy-10E,12Z-octadecadienoic acid (9R-HODE) from linoleic acid was achieved using whole recombinant Escherichia coli cells expressing LOX from Nostoc sp. SAG 25.82. The optimal conditions for the production of 9R-HODE were pH 7.5, 25 °C, 40 g l-1 cells, 15 g l-1 linoleic acid, 2% (v/v) methanol, 1 working volume/oxygen volume/min (vvm) oxygenation rate, and 250 rpm agitation speed in 500 ml-baffled flask containing a working volume of 50 ml. Under these optimized conditions, whole recombinant cells expressing 9R-LOX protein produced 14.3 g l-1 9R-HODE for 1 h, with a conversion yield of 95% (w/w) and a productivity of 14.3 g l-1 h-1. The oxygen supply method significantly influenced stereo- and regio-selectivity of the oxygenation of linoleic acid. Among the oxygen supply methods tested, oxygenation (1 vvm) with agitation (250 rpm) resulted in the highest 9R/13S-HODE ratio of the products at 96:4. This is the first application using whole recombinant cells harboring R-specific LOX for the stereo-selective production of an R-specific hydroxy fatty acid.
ω-alkynyl lipid surrogates for polyunsaturated fatty acids: Free radical and enzymatic oxidations
Beavers, William N.,Serwa, Remigiusz,Shimozu, Yuki,Tallman, Keri A.,Vaught, Melissa,Dalvie, Esha D.,Marnett, Lawrence J.,Porter, Ned A.
, p. 11529 - 11539 (2014/10/15)
Lipid and lipid metabolite profiling are important parameters in understanding the pathogenesis of many diseases. Alkynylated polyunsaturated fatty acids are potentially useful probes for tracking the fate of fatty acid metabolites. The nonenzymatic and enzymatic oxidations of ω-alkynyl linoleic acid and ω-alkynyl arachidonic acid were compared to that of linoleic and arachidonic acid. There was no detectable difference in the primary products of nonenzymatic oxidation, which comprised cis,trans-hydroxy fatty acids. Similar hydroxy fatty acid products were formed when ω-alkynyl linoleic acid and ω-alkynyl arachidonic acid were reacted with lipoxygenase enzymes that introduce oxygen at different positions in the carbon chains. The rates of oxidation of ω-alkynylated fatty acids were reduced compared to those of the natural fatty acids. Cyclooxygenase-1 and -2 did not oxidize alkynyl linoleic but efficiently oxidized alkynyl arachidonic acid. The products were identified as alkynyl 11-hydroxy-eicosatetraenoic acid, alkynyl 11-hydroxy-8,9-epoxy-eicosatrienoic acid, and alkynyl prostaglandins. This deviation from the metabolic profile of arachidonic acid may limit the utility of alkynyl arachidonic acid in the tracking of cyclooxygenase-based lipid oxidation. The formation of alkynyl 11-hydroxy-8,9-epoxy-eicosatrienoic acid compared to alkynyl prostaglandins suggests that the ω-alkyne group causes a conformational change in the fatty acid bound to the enzyme, which reduces the efficiency of cyclization of dioxalanyl intermediates to endoperoxide intermediates. Overall, ω-alkynyl linoleic acid and ω-alkynyl arachidonic acid appear to be metabolically competent surrogates for tracking the fate of polyunsaturated fatty acids when looking at models involving autoxidation and oxidation by lipoxygenases.
Properties of a mini 9R-lipoxygenase from Nostoc sp. PCC 7120 and its mutant forms
Andreou, Alexandra-Zoi,Vanko, Marian,Bezakova, Lydia,Feussner, Ivo
, p. 1832 - 1837 (2008/09/20)
Lipoxygenases (LOXs) consist of a class of enzymes that catalyze the regio- and stereospecific dioxygenation of polyunsaturated fatty acids. Current reports propose that a conserved glycine residue in the active site of R-lipoxygenases and an alanine residue at the corresponding position in S-lipoxygenases play a crucial role in determining the stereochemistry of the product. Recently, a bifunctional lipoxygenase with a linoleate diol synthase activity from Nostoc sp. PCC7120 with R stereospecificity and the so far unique feature of carrying an alanine instead of the conserved glycine in the position of the sequence determinant for chiral specificity was identified. The recombinant carboxy-terminal domain was purified after expression in Escherichia coli. The ability of the enzyme to use linoleic acid esterified to a bulky phosphatidylcholine molecule as a substrate suggested a tail-fist binding orientation of the substrate. Site directed mutagenesis of the alanine to glycine did not cause alterations in the stereospecificity of the products, while mutation of the alanine to valine or isoleucine modified both regio- and enantioselectivity of the enzyme. Kinetic measurements revealed that substitution of Ala by Gly or Val did not significantly influence the reaction characteristics, while the A162I mutant showed a reduced vmax. Based on the mutagenesis data obtained, we suggest that the existing model for stereocontrol of the lipoxygenase reaction may be expanded to include enzymes that seem to have in general a smaller amino acid in R and a bulkier one in S lipoxygenases at the position that controls stereospecificity.
Identification of an amino acid determinant of pH regiospecificity in a seed lipoxygenase from Momordica charantia
Hornung, Ellen,Kunze, Susan,Liavonchanka, Alena,Zimmermann, Grit,Kuehn, Diana,Fritsche, Kathrin,Renz, Andreas,Kuehn, Hartmut,Feussner, Ivo
scheme or table, p. 2774 - 2780 (2009/04/10)
Lipoxygenases (LOX) form a heterogeneous family of lipid peroxidizing enzymes, which catalyze specific dioxygenation of polyunsaturated fatty acids. According to their positional specificity of linoleic acid oxygenation plant LOX have been classified into linoleate 9- and linoleate 13-LOX and recent reports identified a critical valine at the active site of 9-LOX. In contrast, more bulky phenylalanine or histidine residues were found at this position in 13-LOX. We have recently cloned a LOX-isoform from Momordica charantia and multiple amino acid alignments indicated the existence of a glutamine (Gln599) at the position were 13-LOX usually carry histidine or phenylalanine residues. Analyzing the pH-dependence of the positional specificity of linoleic acid oxygenation we observed that at pH-values higher than 7.5 this enzyme constitutes a linoleate 13-LOX whereas at lower pH, 9-H(P)ODE was the major reaction product. Site-directed mutagenesis of glutamine 599 to histidine (Gln599His) converted the enzyme to a pure 13-LOX. These data confirm previous observation suggesting that reaction specificity of certain LOX-isoforms is not an absolute enzyme property but may be impacted by reaction conditions such as pH of the reaction mixture. We extended this concept by identifying glutamine 599 as sequence determinant for such pH-dependence of the reaction specificity. Although the biological relevance for this alteration switch remains to be investigated it is of particular interest that it occurs at near physiological conditions in the pH-range between 7 and 8.
Regio- and stereoselective oxidation of linoleic acid bound to serum albumin: Identification by ESI-mass spectrometry and NMR of the oxidation products
Dufour, Claire,Loonis, Michele
, p. 60 - 68 (2007/10/03)
An efficient RP-HPLC method was developed for the detection of the oxidation products derived from the AAPH-initiated peroxidation of linoleic acid bound to human serum albumin. Diode array UV-detection allowed the quantification at 234 nm of four regioisomeric hydroperoxyoctadecadienoic acids (HPODE) and four hydroxyoctadecadienoic acids (HODE) while at 280 nm four oxooctadecadienoic acid isomers (KODE) were detected. Full identification of the different underivatized HODE, HPODE and KODE isomers was achieved by negative ESI-mass spectrometry outlining common fragmentation pathways for 9- and 13-regioisomers. Chemical synthesis of 9-(E,Z)-, 9-(E,E)-, 13-(Z,E)- and 13-(E,E)-KODE helped to their structural characterization by 1H NMR. Lipid peroxidation in the presence of albumin proved to be regioselective with a larger accumulation of 13-HPODE and 9-KODE isomers. Thermodynamically more stable E,E-stereoisomers were also favored by albumin for both HPODE and KODE.
9-Oxooctadeca-10,12-dienoic acids as Acetyl-CoA carboxylase inhibitors from red pepper (Capsicum annuum L.)
Watanebe, Jun,Kawabata, Jun,Kasai, Takanori
, p. 489 - 493 (2007/10/03)
A methanol extract of red pepper showed potent acetylCoA carboxylase inhibitory activity. The active principles were isolated and identified as (E, E)- and (E, Z)-9-oxooctadeca-10,12-dienoic acids by instrumental analyses. The IC50 values of the compounds were 1.4 x 10-6 and 1.5 x 10-6 M, respectively, their activity being nearly sixty-times higher than that of the common fatty acids themselves. A comparative study of the structure-activity relationship among their related compounds showed that the inhibitory activity was influenced neither by the position and species of the oxygen functional group in the middle of the alkyl chain nor by the configurations of the double bonds. However, it was found that the presence of double bonds between the terminal carboxyl and the mid-chain oxygen functional group lowered the inhibitory activity which could be recovered by hydrogenation of the double bonds.
High-Performance Liquid Chromatographic Analysis of the Products of Linoleic Acid Oxidation Catalyzed by Pea (Pisum sativum) Seed Lipoxygenases
Wu, Zecai,Robinson, David S.,Domoney, Claire,Casey, Rod
, p. 337 - 342 (2007/10/02)
An HPLC method is discussed for the analysis of the products formed by the pea (Pisum sativum) lipoxygenase catalyzed oxidation of linoleic acid.The results demonstrate the feasibility of analyzing all of the hydroperoxides, hydroxides, and keto fatty acids in a single chromatographic step and show that it will be possible to analyze the product profile from the lipoxygenase activity contained in a portion of a seed, which will permit the remainder of the seed to be grown on for subsequent generations.The chemical structures of the products have been identified by HPLC analysis and GC-MS. Keywords: Lipoxygenase; hydroperoxides; chromatography
Lipase Catalysed Regio- and Enantio-selective Hydrolysis: Molecular Recognition Phenomenon and Synthesis of (R)-Dimorphecolic Acid
Bhalerao, U. T.,Dasaradhi, L.,Neelakantan, P.,Fadnavis, N. W.
, p. 1197 - 1198 (2007/10/02)
Molecular recognition has been observed in hydrolysis of racemic esters of (E)-9=acetoxy-11-bromoundec-10-enoic acid by a lipase of Candida cylindracea (E.C. 3.1.1.3) where optically active (R)-(E)-9-acetoxy-11-bromoundec-10-enoic acid 99percent> was obtained which was used in synthesis of (R)-dimorphecolic acid.
Autoxidation of Model Membrane Systems: Cooxidation of Polyunsaturated Lecithins with Steroids, Fatty Acids, and α-Tocopherol
Weenen, Hugo,Porter, Ned A.
, p. 5216 - 5221 (2007/10/02)
The autoxidation of diL-PC and 1S,2A-PC in aqueous emulsion with several cosubstrates was investigated.Cholesterol, 7-dehydrocholesterol, linolic acid, and α-tocopherol were cosubstrates in the autoxidation of dilinoleoylphosphatidylcholine (diLP-PC).The distribution of the products, tc and tt diene hydroperoxides, was determined and evaluated.It was concluded that cholesterol has a lower H atom donating ability (Kp) and 7-dehydrocholesterol a much higher Kp than diL-PC.Linoleic acid when mixed with diL-PC, diP-PC, or a mixture of the two was found to behave analogous to a mixture of just the two lecithins.The cooxidation of diL-PC with a α-tocopherol in the bilayer gave only trans,cis (tc) hydroperoxides, which can be ascribed to a very high kinh for a α-tocopherol, a very efficient antioxidant. 1-Stearoyl-2-arachidonoylphosphatidilcholine (1S,2A-PC)bilayer autoxidation gave a product distribution very similar to arachidonic acid neat autoxidation.However the products from cooxidation of 1S,2A-PC bilayer with α-tocopherol unexpectedly did not include the 5-hydroperoxy eicosatetraenoic acid isomer (5-HPETE), although the 12, 15, 11, 9, and 8 isomers were present in almost equal amounts.
Autoxidation of Polyunsaturated Lipids. Factors Controlling the Stereochemistry of Product Hydroperoxides
Porter, Ned A.,Weber, Bruce A.,Weenen, Hugo,Khan, Jamil A.
, p. 5597 - 5601 (2007/10/02)
The mechanism of the autoxidation of linoleic acid and phospholipid esters of this acid was investigated.The products of autoxidation,13-hydroperoxy-9-cis,11-trans-octadecadienoic (4), 13-hydroperoxy-9-trans,11-trans-octadecadienoic (5), 9-hydroperoxy-10-
