- Influence of fatty acid desaturation on spontaneous acyl migration in 2-monoacylglycerols
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The effect of desaturation from the C9 to the C15 carbon of 2-monoacylglycerol (2-MAG) fatty acids on spontaneous acyl migration is described. Three 2-MAG species, 2-monooleoylglycerol (C18:1 cis-Δ9), 2-monolinoleoylglycerol (C18:2 cis-Δ9,12), and 2-monolinolenoylglycerol (C18:3 cis-Δ9,12,15) were synthesized by lipase-catalyzed ethanolysis of their respective triacylglycerols and isolated in >60 % yield and at 2-MAG purities of >95 % relative to 1-monoacylglycerol (1-MAG). 1H-NMR spectroscopy was used to monitor the spontaneous acyl migration of the 2-MAG species over a temperature range from 20 to 80 °C. The relative energies of activation calculated from the Arrhenius relationships of the 2-MAG acyl migration rate constants were 73.3, 68.0, and 72.9 kJ mol-1 for the three 2-MAG species, respectively. Density functional calculations performed using the B3LYP functional at the 6-31+G* basis set on the three ketal ring intermediate of the three 2-MAG species followed a similar trend with a lack of relative energetic preference associated with the degree of desaturation. The kinetically determined relative activation energies were approximately twofold higher than the theoretical relative Gibbs free energies of the intermediates, suggesting that other factors influence acyl migration. In general, increasing desaturation after the C9 carbon of 2-MAG fatty acids had no appreciable effect on acyl migration rates. AOCS (outside the USA) 2012.
- Compton, David L.,Laszlo, Joseph A.,Appell, Michael,Vermillion, Karl E.,Evans, Kervin O.
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p. 2259 - 2267
(2013/01/15)
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- Application of chemoenzymatic hydrolysis in the synthesis of 2-monoacylglycerols
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The selective biocatalyzed synthesis of 2-monoacylglycerols (2-MAGs) through the use of commercially available immobilized Candida antarctica (Novozym435) and Rhizomucor miehei is explored. Reactions at room temperature result in the formation of a 2-MAG and a corresponding ethyl ester of the fatty acid with immobilized C. antarctica within 2 h with yields ranging from 36% to 83%. Similar reaction conditions with immobilized R. miehei yielded exclusively the 2-MAG after 24 h with yields ranging from 37% to 88%. Yields vary on the acyl group at the sn-2 position and choice of enzyme involved.
- Whitten, Kyle M.,Makriyannis, Alexandros,Vadivel, Subramanian K.
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experimental part
p. 5422 - 5428
(2012/09/08)
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- Biologically active lipids binding membrane receptors
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Neutral lipids are provided characterized by binding to phorboid and ingenoid receptors. These lipids are found in a wide variety of cellular sources as well as milk and may be isolated by specific extraction and chromatographic procedures. Depending upon the source, the glycerides may be mono- or di-glycerides, wherein the total number of carbon atoms of the fatty acids is in the range of 18 to 26, so that the monoglyceride has a fatty acid of at least 18 carbon atoms, while the di-glyceride has a fatty acid of at least 14 carbon atoms.
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