- Distinct roles of adipose triglyceride lipase and hormone-sensitive lipase in the catabolism of triacylglycerol estolides
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Branched esters of palmitic acid and hydroxy stearic acid are antiinflammatory and antidiabetic lipokines that belong to a family of fatty acid (FA) esters of hydroxy fatty acids (HFAs) called FAHFAs. FAHFAs themselves belong to oligomeric FA esters, known as estolides. Glycerol-bound FAHFAs in triacylglycerols (TAGs), named TAG estolides, serve as metabolite reservoir of FAHFAs mobilized by lipases upon demand. Here, we characterized the involvement of two major metabolic lipases, adipose triglyceride lipase (ATGL) and hormone-sensitive lipase (HSL), in TAG estolide and FAHFA degradation. We synthesized a library of 20 TAG estolide isomers with FAHFAs varying in branching position, chain length, saturation grade, and position on the glycerol backbone and developed an in silico mass spectra library of all predicted catabolic intermediates. We found that ATGL alone or coactivated by comparative gene identification-58 efficiently liberated FAHFAs from TAG estolides with a preference for more compact substrates where the estolide branching point is located near the glycerol ester bond. ATGL was further involved in transesterification and remodeling reactions leading to the formation of TAG estolides with alternative acyl compositions. HSL represented a much more potent estolide bond hydrolase for both TAG estolides and free FAHFAs. FAHFA and TAG estolide accumulation in white adipose tissue of mice lacking HSL argued for a functional role of HSL in estolide catabolism in vivo. Our data show that ATGL and HSL participate in the metabolism of estolides and TAG estolides in distinct manners and are likely to affect the lipokine function of FAHFAs.
- Brejchova, Kristyna,Radner, Franz Peter Walter,Balas, Laurence,Paluchova, Veronika,Cajka, Tomas,Chodounska, Hana,Kudova, Eva,Schratter, Margarita,Schreiber, Renate,Durand, Thierry,Zechner, Rudolf,Kuda, Ondrej
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- Highly efficient solvent-free synthesis of 1,3-diacylglycerols by lipase immobilised on nano-sized magnetite particles
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Recently, 1,3-DAGs (1,3-diacylglycerols) have attracted considerable attention as healthy components of food, oil and pharmaceutical intermediates. Generally, 1,3-DAG is prepared by lipase-mediated catalysis in a solvent free system. However, the system's high reaction temperature (required to reach the reactants' melting point), high substrate concentration and high viscosity severely reduce the lipase's activity, selectivity and recycling efficiency. In this report, MjL (Mucor javanicus lipase) was found to have the best performance in the solvent-free synthesis of 1,3-DAGs of several common commercial lipases. By covalent binding to amino-group-activated NSM (nano-sized magnetite) particles and cross-linking to form an enzyme aggregate coat, MjL's specific activity increased 10-fold, and was able to be reused for 10 cycles with 90% residual activity at 55 °C. 1,3-DAGs of lauric, myristic, palmitic, stearic, oleic and linoleic acid were prepared using the resulting immobilised enzyme, all with yields greater than 90%, and the reaction time was also greatly reduced.
- Meng, Xiao,Xu, Gang,Zhou, Qin-Li,Wu, Jian-Ping,Yang, Li-Rong
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p. 319 - 324
(2013/10/08)
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- Lipase-catalyzed transesterification of trilinolein or trilinolenin with selected phenolic acids
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The enzymatic transesterification of selected phenolic acids with TAG, including trilinolein (TLA) and trilinolenin (TLNA), was investigated in an organic solvent medium. Maximal bioconversion of 66% was obtained with a dihydrocaffeic acid (DHCA) to TLA ratio of 1:2 after 5 d of reaction. Similarly, the highest bioconversion of 62% was obtained with a DHCA to TLNA ratio of 1:2, but after 12 d of reaction. However, a ratio of 1:4 DHCA/TLA decreased the bioconversion to 53%. Transesterification reactions of ferulic acid with both TAG, using a ratio of 1:2, resulted in low bioconversion of 16 and 14% with TLA and TLNA, respectively. The overall results indicated that bioconversion of phenolic MAG was higher than that of phenolic DAG. The structures of mono- and dilinoleyl dihydrocaffeate as well as those of mono- and dilinolenyl dihydrocaffeate were confirmed by LC-MS analyses. The phenolic lipids demonstrated moderate radical-scavenging activity. Copyright
- Sabally, Kebba,Karboune, Salwa,St-Louis, Richard,Kermasha, Selim
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p. 101 - 107
(2007/10/03)
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- Enzymatic synthesis of symmetrical 1,3-diacylglycerols by direct esterification of glycerol in solvent-free system
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1,3-Diacylglycerols were synthesized by direct esterification of glycerol with free fatty acids in a solvent-free system. Free fatty acids with relatively low melting points (45°C) such as unsaturated and medium-chain saturated fatty acids were used. With stoichiometric ratios of the reactants and water removal by evaporation at 3 mm Hg vacuum applied at 1 h and thereafter, the maximal 1,3-diacylglycerol content in the reaction mixture was: 84.6% for 1,3-dicaprylin, 84.4% for 1,3-dicaprin, 74.3% for 1,3-dilinolein, 71.7% for 1,3-dieicosapentaenoin, 67.4% for 1,3-dilaurin, and 61.1% for 1,3-diolein. Some of the system's parameters (temperature, water removal, and molar ratio of the reactants) were optimized for the production of 1,3-dicaprylin, and the maximal yield reached 98%. The product was used for the chemical synthesis of 1,3-dicapryloyl-2-eicosapentaenoylglycerol. The yield after purification was 42%, and the purity of the triacylglycerol was 98% (both 1,3-dicapryloyl-2-eicosapentaenoylglycerol and 1,2-dicapryloyl-3-eicosapentaenoylglycerol included) by gas chromatographic analysis, of which 90% was the desired structured triacylglycerol (1,3-dicapryloyl-2-eicosapentaenoylglycerol) as determined by silver ion high-performance liquid chromatographic analysis.
- Rosu, Roxana,Yasui, Mamoru,Iwasaki, Yugo,Yamane, Tsuneo
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p. 839 - 843
(2007/10/03)
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