Linolenic acid conversion

Goyens, RL.L. M.E. Spilker EL. Zock M.B. Katan R.P. Mensink. Compartmental modeling to quantify alpha -linolenic acid conversion after longer rerm intake of multiple tracer boluses. J. Lipid Res. 2005, 46, 1474-1483. 

Fig. 4. Effect of insulin concentration on linolenic acid conversion to 20 5 (5, 8, 11, 14, 17) acid and 20 3 (11, 14, 17) acid by HTC cells.

Figure 11.13 The pathways in Figures 11.11 and 11.12 are presented side by side for comparison. The pathways are known as the omega-6 and the omega-3 pathways. Both linoleic and a-linolenic acids are, in general, present in sufficient amounts in the diet of humans to provide adeguate amounts of arachidonic and eicosapentaenoic acids, but the enzymes in the two pathways must be sufficiently active for conversions to occur (see below).

Based on mechanistic studies, the antioxidant property of diaryl teUurides is related to their conversion into 4,4 -disubstituted telluroxides. Also has been described to retard peroxidation of linolenic acid in methanol. ... 

FIGURE 21-12 Routes of synthesis of other fatty acids. Palmitate is the precursor of stearate and ionger-chain saturated fatty acids, as well as the monounsaturated acids palmitoleate and oleate. Mammals cannot convert oleate to linoleate or a-linolenate (shaded pink), which are therefore required in the diet as essential fatty acids. Conversion of linoleate to other polyunsaturated fatty acids and eicosanoids is outlined. Unsaturated fatty acids are symbolized by indicating the number of carbons and the number and position of the double bonds, as in Table 10-1. 

Figure 21-3 Major pathways of synthesis of fatty acids and glycerolipids in the green plant Arabidopsis. The major site of fatty acid synthesis is chloroplasts. Most is exported to the cytosol as oleic acid (18 1). After conversion to its coenzyme A derivative it is converted to phosphatidic acid (PA), diacylglycerol (DAG), and the phospholipids phosphatidylcholine (PC), phosphatidylinositol (PI), phosphatidylglycerol (PG), and phosphatidylethanolamine (PE). Desaturation also occurs, and some linoleic and linolenic acids are returned to the chloroplasts. See text also. From Sommerville and Browse.106 See also Figs. 21-4 and 21-5. Other abbreviations monogalactosyldiacylglycerol (MGD), digalactosyldiacylglycerol (DGD), sulfolipid (SL), glycerol 3-phosphate (G3P), lysophosphatidic acid (LPA), acyl carrier protein (ACP), cytidine diphosphate-DAG (CDP-DAG).

The conversion of oleoyl-CoA to linoleoyl-CoA is accomplished by some insects118 but does not take place in most animals. As a result of this biosynthetic deficiency, polyunsaturated fatty acids such as linoleic, linolenic, and the C20 arachidonic acid are necessary in the diet (Box 21-B). One essential function of linoleic acid is to serve as a precursor of prostaglandins and related prostanoids (Section D). Dietary linoleate is converted to its Co A derivative and then by sequential A6 desaturation,119 elongation, and then A5 desaturation, to the 20 4 (A5 8 11 14) arachidonoyl-CoA (Fig. 21-2, lower right). These acids are referred to as 0)6 because of the position of the last double bond. Linolenic acid can be converted in an analogous fashion to the CoA derivative of the 20 5 (A5 8 11 14 17 co6) eicosapentaenoic acid (EPA). The 22 6 docasahexaenoic acid (DHA Fig. 21-2) is apparently formed by elongation of the 22 5 acyl-CoA to 24 5, desaturation, transfer to a peroxisome or mitochondrion, and p oxidation to shorten the chain.953... 

Hussein, N., Ah-Sing, E., Wilkinson, P., Leach, C., Griffin, B.A., and Millward, D.J. 2005. Long-chain conversion of [13C] linoleic acid and a-linolenic acid in response to marked changes in their dietary intake in men. J. Lipid Res. 46, 269-280. 

Vermunt, S.H.F., Mensink, R.P., and Simonis, M.M.G. 2000. Effects of dietary alpha-linolenic acid on the conversion and oxidation of 13C-alphalinolenic acid. Lipids 35, 137-142. 

Yamada, K., Kobayashi, K. and Yone, T. (1980). Conversion of linolenic acid to 3 highly unsaturated fatty acids in marine fishes and rainbow trout. Bulletin of the Japanese Society of Scientific Fisheries 46,1231-1238. 

I Average conversion yield Linolenic acid methyl ester Linoleic acid methyl ester Oleic acid methyl ester... 

Rapeseed oil and its fatty acids (stearic, palmitic, oleic, linoleic, and linolenic acids) were chosen as the samples of vegetable oil. The experiments were performed in the batch- and flow-type supercritical biomass conversion systems developed in our laboratory. For the batch-type system, a reaction vessel was made of Inconel-625 with a volume of 5 mL for the flow-type system, the supercritical treatment tube was constructed from Hastelloy stainless steel (HC 276) with length of 84 m and an id of 1.2 mm, with the total volume being about 95 mL. Detailed information about the equipment can be found elsewhere (13). 

Fell et al. presented a micellar two-phase system in which fatty acid esters can be hydroformylated [30]. Short fatty acids react in a mixture of water and the substrate without adding any surfactants. The rhodium/NaTPPTS catalyst system was able to conduct the reaction of methyl 10-undecenoate at 100°C with 30-bar synthesis gas pressure with a conversion of 99% without any surfactant. The reaction of linolenic acid ester was hindered by phase transfer problems which could be overcome by employing surfactants. The addition decreased the reaction time, so the same rhodium catalyst could achieve a conversion for linolenic methyl ester of 100%. The authors... 

FIGURE 26.2 Metabolic conversion of linoleic acid and a-linolenic acid to longer chain, more unsaturated fatty acids. 

Emken, E.A. (1995) Influence of linoleic acid on conversion of linolenic acid to omega-3 fatty acids in humans, in Proceedings from the Scientific Conference on Omega-3 Fatty Acids in Nutrition, Vascular Biology, and Medicine. American Heart Association, Dallas, Texas, USA, pp. 9-18. 

Since Wallen et al. (1962) reported the first bioconversion of oleic acid to 10-hydroxystearic acid by a Pseudomonad, microbial conversions of unsaturated fatty acids from different substrates by various microbial strains have been widely exploited to produce new, value-added products. Among the unsaturated fatty acids used for microbial production of hydroxy fatty acids, three (oleic, linoleic, and linolenic acids) were well studied as substrates to produce mono-, di-, and trihydroxy fatty acids. Recently, a bacterial strain Pseudomonas aeruginosa NRRL B-18602 (PR3) has been studied to produce hydroxy fatty acids from several fatty acid substrates. In this review, we introduce the production of hydroxy fatty acids from their corresponding fatty acid substrates by P. aeruginosa PR3 and their industrially valuable biological activities. 

Kamisaka, Y., Yokochi, T., Nakahara, T., and Suzuki, O. 1990. Incorporation of lin-oleic acid ind its conversion to y-linolenic acid in fungi. Lipids, 25,54-60. 

Essential fatty acids (EFAs) are essential for the survival of humans and other mammals they cannot be synthesized in the body and, hence, have to be obtained in our diet and, thus, are essential (1-4). EFAs are an important constituent of cell membranes and confer on membranes properties of fluidity thus, they determine and influence the behavior of membrane-bound enzymes and receptors. Two types of naturally occurring EFAs exist in the body the oo-6 series derived from linoleic acid (LA, 18 2) and the oo-3 series derived from a-linolenic acid (ALA, 18 3). Both the 00-6 and the oo-3 series are metabolized by the same set of enzymes to their respective long-chain metabohtes. Although some functions of EFAs require their conversion to eicosanoids and other products, in most instances the fatty acids themselves are active. The longer-chain metabolites of LA and ALA regulate membrane function and are of major importance in the brain, retina, liver, kidney, adrenal glands, and gonads. 

Polyunsaturated fatty acids such as linolenic acid (C18 3) are hydrogenated more quickly to linoleic (C18 2) or oleic acid (C18 1) than linoleic to oleic acid or oleic acid to stearic acid (C18 0). The conversion steps can be represented as follows ... 

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