Chain fatty acid ester

Smith and Stirton applied this mechanism to the sulfonation of long-chain fatty acid esters [31]. Instead of forming the well-defined mixed anhydride during the reaction of fatty acids with S03, the acid esters form a complex less defined in structure and composition. In this complex the a-hydrogen is activated, so that a second molecule of S03 can react. These two addition steps are fast. The final step is again a slow rearrangement of the intermediate with a loss of one molecule of S03. 

PGF2a-1,15-lactone-11-acetate (140) and PGF3ct-l,15-lactone-11-acetate (141) [174-176]. Further, T. fimbria reproductive tissues and egg masses contained a relatively high concentration of saturated and unsaturated long-chain fatty acid esters of PGF2 and PGF3(r (142, 143) [177, 178]. 

The surface shear viscosity of a monolayer is a valuable tool in that it reflects the intermolecular associations within the film at a given thermodynamic state as defined by the surface pressure and average molecular area. These data may be Used in conjunction with II/A isotherms and thermodynamic analyses of equilibrium spreading to determine the phase of a monolayer at a given surface pressure. This has been demonstrated in the shear viscosities of long-chain fatty acids, esters, amides, and amines (Jarvis, 1965). In addition,... 

The long-chain, fatty acid esters of sucrose are non-ionic, nontoxic, and biodegradable, and compare well in overall performance with other surface-active compounds in detergency, emulsification, and... 

In many tissues cholesterol and other sterols exist as a mixture of the free alchohol and its long chain fatty acid ester (esterified at position 3 of the steroid nucleus). The determination of the cholesterol content of a sample may involve the measurement of either of these two fractions individually or the total cholesterol. It is possible to precipitate free cholesterol by adding an equal volume of digitonin (1 gl-1 in 95% ethanol), a naturally occurring glu-coside, to form a complex that is insoluble in most solvents, including water. 

Cataldo F, Braun T (2007) Solubility of C fullerene in long chain fatty acid esters. Fullerenes Nanot. Carbon Nanostruct. 15 331-339. 

The synthesis of long-chain fatty acid esters of carbohydrates is inherently more demanding. It was found that glucose did not react with vinyl laurate in a pure ionic liquid medium, but in biphasic tert-butyl alcohol/[BMIm][PF6], glucose could be acylated by the vinyl esters of O, 2-Cu, fatty acids. The best results were obtained with CaLB, which was twice as active as TIL, and the selectivity for acylation at C-6 was high [114]. The esterification of glucose with palmitic acid, which is, in an industrial context, to be preferred over transesterification, has recently been demonstrated in tert-butyl alcohol/[BMIm][PF6] medium [115]. 

The chromatographic profiles representing saturated mono-, di-, and polyunsaturated long-chain fatty acid esters from marine triacylglycerols were very complex. In general, polyunsaturates are eluted before saturates of equal chain length and shorter-chain before longer-chain fatty acid esters. 

Radiation Biochemistry of Lipids. The rancidity that develops in stored fish is the result of oxidative reactions. Work being done with methyl docosahexaenoate shows that irradiation per se does not cause observable or measurable changes in this long-chain fatty acid ester. However, changes involving fatty acids go on at a higher rate in irradiated fishery products than in the nonirradiated counterparts (16). 

Methyl Esters. These esters can be isolated and purified by thin-layer chromatography on silica gel G with a solvent system of petroleum ether (b.p. 30-60°)-diethyl ether (80 20, v/v). Usually these esters exhibit an /Rvalue in the range of 0.80-0.85. Their characterization can be achieved in a manner similar to that described in Chapter 4. Thus, a combination of gas-liquid chromatography and mass spectrometry will afford a detailed insight into the structure and composition of these long-chain fatty acid esters. 

The current world production of fats and oils is around 65 MM metric tons of which 30 percent is from animal sources and 70 percent is of vegetable origin. Fats and oils are composed of long chain fatty acid esters of glyc-... 

The repair and replication of cells involves metabolism - interconversions of hundreds of low molecular weight metabolites that ultimately yield the precursors for much larger, more complex macromolecules such as phospholipids (based on phosphatidic. acids or long chain fatty acid esters of glycerol phosphate), polynucleotides such as RNA and DNA (polymers of nucleotide monomers), proteins (polypeptides or amino acid monomers linked by peptide bonds) and polysaccharides (polymers of simple sugars or monosaccharides). 

Waxes are present as long-chain fatty acid esters with fatty alcohols, methanol, and ethanol. Fatty acid analysis showed that behenic (C 22), lignoceric (C 24), and palmitic acids (C 16) are the major fatty acid for longer alkyl esters and oleic and palmitic for the shorter alkyl esters (Table 4) (24). The major alcohols found are for longer alkyl esters. These are as follows ... 

Branched-chain fatty acid esters, such as glyceryl di-isostearate and di-isostearyl malate, have... 

We should note, however, that incorporation of a substrate into a micelle will accelerate its reaction with a micelle counterion only if the substrate is bound at the micellar surface, since ionic reagents cannot, apparently, penetrate into the micellar core. Thus, the hydroxyl ion-catalyzed hydrolysis of long-chain fatty acid esters of 3-nitro-4-hydroxybenzenesulfonic acid was inhibited by incorporation into micelles no matter whether these were uncharged, anionic, or cationic (68). 

It was observed that yeast production of middle-chain fatty acid esters, and acetates of alcohols formed by reduction of the correspondent... 

Sucrose polyester - In normal volunteers, doses of 8-25 g/day of sucrose polyester, a liquid non-hydrolyzable unabsorbable long chain fatty acid ester of sucrose, lowered total and LDL-C without altering serum triglycerides or HDL-C. The material inhibited cholesterol absorption and increased the excretion of neutral sterols and bile acids. 

The blood and tissues of animals typically contain not only unesterified cholesterol (UC), but also cholesterol esters (CE). Most of the CE are formed from long-chain fatty acids such as palmitic acid, oleic acid, linoleic acid, or arachidonic acid, but small amounts of cholesterol sulfate (CS) and cholesterol glucuronide also are present. The aim of this chapter is to provide a brief overview of the biochemistry, physiology, and pathology of these esters as an introduction to the field of CE research. The primary focus will be on long-chain fatty acid esters because much more is known about them than about other CE. However, current knowledge of the biochemistry of CS will be reviewed as well. 

The distribution of UC and CE in 22 rat tissues is shown in Table 1. It will be seen that CE comprise only about one-eighth of the total body cholesterol, and that long-chain fatty acid esters of cholesterol predominate over CS. It is clear also that long-chain fatty acid esters of cholesterol are distributed very unevenly among different tissues. They are essentially absent from erythrocytes and are present in only extremely low amounts in tissues of the nervous system. On the other hand, they are present in relatively high amounts in the adrenal, ovaries and blood plasma, and the liver, too, can be relatively rich in CE. 

Table 2 shows that UC and long-chain fatty acid esters of cholesterol are also distributed unevenly among the membranes and organelles of individual cells. (No information is available about the intracellular distribution of CS or cholesterol... 

Studies of the physical properties of UC, reviewed in Chapter 6 of this volume, have contributed much to our understanding of the role of this Upid in membranes and lipoprotein surfaces. The shape and polarity of UC promote its association with the phosphoUpids of membranes and Upoproteins, and this association has important effects on membrane fluidity and permeability. The physical properties of long-chain fatty acid esters of cholesterol, on the other hand, differ strikingly from those of UC, and cause these esters to be largely excluded from phospholipid bilayers and monolayers and to aggregate instead in oil droplets. 

Long-chain fatty acid esters of cholesterol are much bulkier than is UC, and lack a polar hydroxyl group. They do not become hydrated in the presence of water, and are essentiaUy water insoluble. When mixed with water they form a floating oil phase, unlike UC, which forms a film [11], They mix with phosphoUpids only in very... 

Nearly all animal cells contain an enzyme that can catalyze the formation of long-chain fatty acid esters of cholesterol. This enzyme, ACAT, is associated with the endoplasmic reticulum [15,18] and appears to be an integral membrane protein [16,19]. It catalyzes the following reaction ... 

---