Derived lipids

Eicosanoid (Section 27.4) A lipid derived biologically from 5,8.11,14-eicosatetraenoic acid, or arachidonic acid. Prostaglandins, thromboxanes and leukotrienes are examples. 

Prostaglandin (Section 27.4) A lipid derived from arachi-donic acid. Prostaglandins are present in nearly all body tissues and fluids, where they serve many important hormonal functions. 

Morrow JD, Roberts LJII (2001) Lipid-derived autacoids. In Hardman JG, Limbird LE, Gilman AG (eds), Goodman and Gilman s the pharmacological basis of therapeutics. New York, McGraw-Hill, pp 669-685... 

SKIBSTED L H, MiKKELSEN A and BERTELSEN G (1998) Lipid-derived off-flavours in meat, in Shahidi F Flavour of Meat, Meat Products and Seafoods, Blackie Academic Professional, London, 217-56. 

LOO, the peroxyl radical LH, the lipid substrate L, the lipid-derived alkyl radical AH, a chain-breaking antioxidant A, the antioxidant-derived radical. Copper is the catalyst in this reaction and would also form the alkoxy radical as shown in Reaction 2.9 (see text), which is omitted here for the sake of clarity. 

Oxidation of the fatty acids in an LDL particle shares many of the characteristics associated with lipid peroxidation in other biological or chemical systems. Once initiated peroxyl radicals are formed and this results in the oxidation of a-tocopherol to give the a-tocopheroyl radical (Kalyanaraman etal., 1990). This can be demonstrated by e.s.r. techniques that allow the direct observation of stable radicals such as the a-tocopheroyl radical. After the a-tocopheryl radical is consumed, lipid-derived peroxyl radicals can be detected after reaction with spin traps (Kalyanaraman etal., 1990, 1991). 

The reactions described so far do not require the involvement of the apo-B protein, neither would they necessarily result in a significant amount of protein modification. However, the peroxyl radical can attack the fatty acid to which it is attached to cause scission of the chain with the concomitant formation of aldehydes such as malondialdehyde and 4-hydroxynonenal (Esterbauer et al., 1991). Indeed, complex mixtures of aldehydes have been detected during the oxidation of LDL and it is clear that they are capable of reacting with lysine residues on the surface of the apo-B molecule to convert the molecule to a ligand for the scavenger receptor (Haberland etal., 1984 Steinbrecher et al., 1989). In addition, the lipid-derived radical may react directly with the protein to cause fragmentation and modification of amino acids. 

Tulasi SJ, Reddy PUM, Rao JV. 1992. Accumulation of lead and effects on total lipids and lipid derivatives in the freshwater fish Anabas testudineus (Bioch). Ecotoxicol Environ Safety 23 33-38. 

In case of scavenging of lipid-derived peroxyl radicals (LOO"), the radical adduct formed [LOO-CaiT is less reactive than the LOO, so carotenoids act as chain-breaking antioxidants in lipid peroxidation (Equation 15.6) ... 

Campbell, W.B. and Halushka, P. V., Lipid-derived autacoids eicosanoids and platelet-activating factor, in Goodman and Gilman s The Pharmacological Basis of Therapeutics, 9th ed., Hardman, J.G. and Limbird, L.E., Eds., McGraw-Hill,... 

Plants were probably the first to have polyester outerwear, as the aerial parts of higher plants are covered with a cuticle whose structural component is a polyester called cutin. Even plants that live under water in the oceans, such as Zoestra marina, are covered with cutin. This lipid-derived polyester covering is unique to plants, as animals use carbohydrate or protein polymers as their outer covering. Cutin, the insoluble cuticular polymer of plants, is composed of inter-esterified hydroxy and hydroxy epoxy fatty acids derived from the common cellular fatty acids and is attached to the outer epidermal layer of cells by a pectinaceous layer (Fig. 1). The insoluble polymer is embedded in a complex mixture of soluble lipids collectively called waxes [1], Electron microscopic examination of the cuticle usually shows an amorphous appearance but in some plants the cuticle has a lamellar appearance (Fig. 2). 

Kolattukudy PE (1987) Lipid derived defensive polymers and waxes and their role in plant-microbe interaction. In Stumpf PK (ed) The biochemistry of plants vol 9 - lipids structure and function. Academic Press, New York, p 291... 

Figure 22.11 A sulfhydryl-reactive lipid derivative may be prepared through the reaction of SMPB with PE to produce a maleimide-containing intermediate. Sulfhydryl-containing molecules then may be coupled to the phospholipid via stable thioether linkages.

Goundalkar, A., Chose, T., and Mezei, M. (1983) Covalent binding of antibodies to liposomes using a novel lipid derivative. /. Bharm. Pharmacol. 36, 465-466. 

It should be noted that Reaction (4) is not a one-stage process.) Both free radical N02 and highly reactive peroxynitrite are the initiators of lipid peroxidation although the elementary stages of initiation by these compounds are not fully understood. (Crow et al. [45] suggested that trans-ONOO is protonated into trans peroxynitrous acid, which is isomerized into the unstable cis form. The latter is easily decomposed to form hydroxyl radical.) Another possible mechanism of prooxidant activity of nitric oxide is the modification of unsaturated fatty acids and lipids through the formation of active nitrated lipid derivatives. 

Smith, E. B., and Cochran, S., Factors influencing the accumulation in fibrous plaques of lipid derived from low-density lipoprotein II. Preferential immobilization of lipoprotein(a) [Lp(a)]. Atherosclerosis (Shannon, Irel.) 84, 173-181 (1990). 

Richard C, Balavoine F, Schultz P, Ebbesen TW, Mioskowski C (2003) Supramolecular self-assembly of lipid derivatives on carbon nanotubes. Science 300 775-778. 

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