With long-chain fatty acids

Sucrose polyesters, which are made by esterilying sucrose with long-chain fatty acids, have the physical properties of fat, but are resistant to digestive enzymes (40). Olestra, a sucrose polyester developed by Procter Gamble, was submitted for regulatory approval in May 1987. In order to faciUtate the approval process, Procter Gamble has since narrowed the scope of its food additive petition to include olestra s use only in savory and extmded snacks. 

Inversion ofMon cjueous Polymers. Many polymers such as polyurethanes, polyesters, polypropylene, epoxy resins (qv), and siHcones that cannot be made via emulsion polymerization are converted into latices. Such polymers are dissolved in solvent and inverted via emulsification, foUowed by solvent stripping (80). SoHd polymers are milled with long-chain fatty acids and diluted in weak alkaH solutions until dispersion occurs (81). Such latices usually have lower polymer concentrations after the solvent has been removed. For commercial uses the latex soHds are increased by techniques such as creaming. 

Although both estrone and estradiol are available for replacement therapy, they suffer the disadvantage of poor activity on oral administration and short duration of action even when administered parenterally, because of ready metabolic disposition. In order to overcome these deficiencies, there was developed a series of esters of estradiol with long-chain fatty acids. These esters are oil-soluble and correspondingly water-insoluble compounds. 

In the case of androgens as with estrogens there is occasionally need for treatment of patients with chronic sustained doses of these drugs. Resort is made to esters of the androgen with long-chain fatty acids in order to provide oil-soluble agents ... 

Triacylglycerol (Section 27.1) A lipid, such as those found in animal fat and vegetable oil. that is, a triester of glycerol with long-chain fatty acids. 

A mechanism Is proposed by which water-insoluble plant lipids (sterols etc.) may act as allelochemicals via micelle formation with long-chain fatty acids. By this process plant lipid solubility and transport In the aqueous medium are enhanced. This might suggest a reevaluation of water-insoluble plant constituents such as sterols as potential allelopathic agents. 

The amino group of sphingosine is acylated with long-chain fatty acids and the N-acylated product is termed a ceramide (Fig. 3-3). C-l of ceramide is linked to different... 

Esterification of at least 45% of the hydroxyl groups with long chain fatty acids, e.g., stearic or behenic acid, results in a semi crystalline material (side chain crystallization). The obtained materials are characterized by melting point ranges which are approximately 10 °C lower than the comparable methyl esters. 

A summary of the sources and fates of fatty acids and ketone bodies is presented in Figure 7.1 and Table 7.1. A major problem with long-chain fatty acids and TAGs is their lack of solubility in the aqueous medium of the blood and interstitial fluid. How this is overcome for fatty acids is discussed in this chapter, and for triacylglycerol in Chapter 11. Unfortunately, the need to transport relatively large quantities of triacylglycerol in the blood can lead to pathological problems (Chapter 11). 

Figure 7.11 Mechanism of transport of long-chain fatty adds across the inner mitochondrial membrane as fatty acyl carnitine. CRT is the abbreviation for carnitine palmitoyl transferase. CPT-I resides on the outer surface of the inner membrane, whereas CPT-II resides on the inner side of the inner membrane of the mitochondria. Transport across the inner membrane is achieved by a carrier protein known as a translocase. FACN - fatty acyl carnitine, CN - carnitine. Despite the name, CRT reacts with long-chain fatty acids other than palmitate. CN is transported out of the mitochondria by the same translocase.

The initial reactions produce phosphatidate, in which the two hydroxyl groups of glycerol 3-phosphate are esterified with long-chain fatty acids, catalysed by enzymes known as acyltransferases. An important point is that, due to the difference in specificities of the acyltransferase enzymes. 

Fats and oils are esters of the trihydric alcohol glycerol with long-chain fatty acids. The descriptor fat or oil is applied according to whether the material is a solid or liquid at room temperature it has no chemical meaning. All three fatty acids in the ester may be the same, or they may be different. Common saturated fatty acids... 

Fat degradation provides a major source of energy for most organisms. Fats are esters of glycerol with long-chain fatty acids (see Box 7.16) and are hydrolysed... 

Uses. Reacts with long-chain fatty acids to form ethanolamine soaps, which are used extensively as emulsifiers, thickeners, wetting agents, and detergents in cosmetic formulations also used as a dispersing agent in agricultural chemicals as a chemical intermediate as a corrosion inhibitor... 

Mammalian cells acquire cholesterol either by de novo synthesis from acetyl-coen-zyme A (CoA) or via the low-density lipoprotein (LDL)-receptor-mediated uptake of LDL particles that contain cholesterol esterified with long-chain fatty acids. These LDL cholesterol esters are subsequently hydrolyzed in lysosomes, after which free cholesterol molecules become available for synthesis of membranes, steroid hormones, bile acids, or oxysterols [1]. 

Retinol A primary alcohol containing a p-ionone ring with an unsaturated side chain, retinol is found in animal tissues as a retinyl ester with long-chain fatty acids. 

The second major type of lipid found in some biological membranes is cholesterol. Cholesterol (fig. 17.5) is an isoprenoid compound with four fused rings, a short aliphatic chain, and a single hydroxyl group. It occurs in membranes both in its free form and esterified with long-chain fatty acids. Table 17.3 compares the lipid compositions of mem-... 

V. Derevitskaya Structure of carbohydrate chains of blood group glycoproteins C. E. Ballou The specific interaction of mycobacterial polymethylsaccharides with long-chain fatty acids... 

Figure 11 Schematic representation of the energy transfer to a trap site, formed during irradiation, depending on the molar fraction of CUA in mixed LB films with long chain fatty acids which are not shown for simplicity.

Dasgupta P, Singh A, Mukherjee R (2002) N-terminal acylation of somatostatin analog with long chain fatty acids enhances its stability and anti-proliferative activity in human breast adenocarcinoma cells. Biol Pharm Bull 25 29-36 Delgado C, Francis GE, D. F (1992) The uses and properties of PEG-linked proteins. Crit Rev Ther Drug Carrier Syst 9 249-304... 

The surface layer of the fat globule may act as a catalytic impurity (e.g., when it contains mono-glycerides or di-glycerides with long-chain fatty acid residues) however, there is still some uncertainty as to whether this process actually occurs (see Walstra, 1995). Although concentric layers of apparently crystalline fat have been observed in electron micrographs of freeze-etched or freeze-fractured milk or cream samples (Buchheim, 1970 Henson et al., 1971), these observations could not be confirmed by other microscopy techniques. Noda and Yamamoto (1994) reported that it is thermodynamically more favorable for fat crystals to be located at the oil/water interface, rather than in the interior of the droplet, which may explain the presence of fat crystals at the membrane. 

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