Phospholipid fatty acids

Numerous methods have been developed for attaching ligands to the surface of liposomes for reviews, see Refs. (3,6 ). For peptides, they fall into two major categories (i) covalent coupling of the peptides to preformed liposomes that contain functionalized hydrophobic anchors such as, e.g., derivatives of phos-phatidylethanolamine (PE) or (ii) incorporation of lipopeptides, obtained by conjugation of peptides to hydrophobic anchors (fatty acids, phospholipids), into liposomes either during the preparation of the vesicles or by postinsertion into preformed vesicles. In this section, we will briefly discuss these techniques and focus on the ones we have been using in our own work. 

Polyunsatmated (essential) fatty acids phospholipids membranes... 

The heterogeneous class of compounds marked by solubility in so-called lipid solvents (acetone, hydrocarbons, ether, etc.) and relative insolubility in water, has traditionally been called lipids (3). This historical classification, based upon isolation procedures from natural products, is obviously too broad for simple generalizations since it includes triglycerides, fatty acids, phospholipids, sterols, sterol esters, bile acids, waxes, hydrocarbons, fatty ethers and hydrocarbons. For the purposes of this chapter, we will consider lipids to be fatty acids and their derivatives. 

Fats, oils, fatty acids, phospholipids, and sterols. 

Biochemically, the pantothenate coenzymes are integral in the metabolism of carbohydrates, lipids, and nitrogen-containing compounds (185,186). They participate in the TCA or Krebs cycle, as well as fatty acid, phospholipid, sterol (cholesterol), and heme synthesis. The coenzymes mediate the exchange of 2-carbon (acetyl) and other acyl groups. They can serve as... 

Fatty acids, phospholipids, etc., on water often show the following phases [582-584] (Fig. 13.3) ... 

Albumin is the main plasma protein, with a molecular weight of about 69 kDa, and is important for normal plasma oncotic pressure and the transport of many biologically active substances, including free fatty acids, phospholipids (e.g., lysophosphatidic acid), prostanoids, heavy metals, steroid hormones, and vitamins. Albumin-bound lysophosphatidic acid serves as a survival factor for cultured mouse proximal tubular cells (L4). Lysophosphatidic acid is an exquisitely potent inhibitor of apoptosis, comparable with growth factors, for example, EGF. The influence of lysophosphatidic acid on the survival of tubular cells depends on the activation of phophatidylinositol 3-kinase (PI3K) with subsequent activation of Akt and pp70s6k. pp70s6k is a rapamycin-inhibited kinase, which plays an important role in the cellular proliferation. Lysophosphatidic acid also serves as a proliferation factor of mouse proximal tubular cells. Further albumin-bound factors important for the survival of the proximal tubular cells are phosphatidic acid... 

The applications of PM-IRRAS also include fatty acids, phospholipids, and protein conformations. Desbat and co-workers reported on the variation of the dissociation of a Langmuir monolayer of arachidic acid at the air-water interface as a function of the subphase pH and for several cations (Cd2+, Ca2 +, Mg2 +, and Na+) with the help of the PM-IRRAS method [92]. Fig. 14 shows the PM-IRRAS spectra of Langmuir monolayer of deuterated arachidic acid in the presence of CdCb as a function of the subphase pH. At low subphase pH (pH = 3.5), the spectrum only presents absorption bands related to the acid form, i.e., the C = O stretching vibration (v(C = O)) and the OH bending (<5(0-H)) located at 1720 and 1270 cm respectively. The frequency position of the v(C = O) is characteristic of a hydrogen-bonded carbonyl group. As the subphase pH is increased, the arachidic acid is progressively deprotonated to... 

The composition and structure of bovine milk fat have been reviewed extensively. There are early reviews by Morrison (1970), Christie (1978, 1995), Jensen and Clark (1988), and Jensen and Newberg (1995) recent articles include a comprehensive review of recent research by Jensen (2002) and two book chapters by Vanhoutte and Huyghebaert (2003), and Zegarska (2003). Bovine milk lipids are similar to the milk lipids of other species as they are largely composed of triacylglycerols however, there are also minor amounts of diacyl-glycerols, monoacylglycerols, free (unesterified) fatty acids, phospholipids and... 

Canola Oil occurs as a light yellow oil. It is typically obtained by a combination of mechanical expression followed by n-hexane extraction, from the seed of the plant Brassica juncea, Brassica napus, or Brassica rapa (Fam. Cruciferae). The plant varieties are those producing oil-bearing seeds with a low erucic acid (C22 i) content. It is a mixture of triglycerides composed of both saturated and unsaturated fatty acids. It is refined, bleached, and deodorized to substantially remove free fatty acids phospholipids color odor and flavor components and miscellaneous, other non-oil materials. It can be hydrogenated to reduce the level of unsaturated fatty acids for functional purposes in foods. It is a liquid at 0° and above. 

Coconut Oil (Unhydrogenated) occurs as a viscous, white to light yellow-tan liquid. It is obtained from the kernel of the fruit of the coconut palm Cocos nucifera (Fam. Palmae). The crude oil obtained by mechanically pressing dried coconut meat (copra) is refined, bleached, and deodorized to substantially remove free fatty acids, phospholipids, color, odor and flavor components, and other non-oil materials. Compared with many natural fats, Coconut Oil (Unhydrogenated) has an abrupt melting range, changing from a rather firm, plastic solid at about 21° or below to a liquid at about 21°. 

Solin Oil occurs as a light yellow oil. It is obtained from the seed of certain varieties of the flaxseed plant Linum usitatissi-mum L. (Fam. Linaceae) by mechanical expression and/or solvent extraction, differing from linseed oil in having a linolenic acid (C18 3) content of less than 5%. The oil is refined, bleached, and deodorized to remove free fatty acids, phospholipids, color, odor and flavor components, and miscellaneous non-oil materials. It is liquid and free from visible foreign material at 21° to 21°, but traces of wax may cause the oil to cloud at refrigeration temperatures (2° to 5°) unless removed by winterization. 

Naturally occurring oils and fats constitute another important source of renewable raw materials [198]. Whether they are referred to as fats or oils depends on whether they are solid or liquid at room temperature, respectively. They are composed primarily of triglycerides (triesters of glycerol) together with small amounts of free fatty acids, phospholipids, sterols, terpenes, waxes and vitamins. Oils and fats are either of vegetable or animal origin and are produced in the approximate proportions 55% vegetable oils, 40% land-animal fats and 5% marine oils [199]. 

The development of oxidative flavors and off-flavors is an Important factor in acceptance or rejection of cooked meats. One of the Important reactions Involved in the formation of volatile compovinds In meat, and meat products In general, is the autoxidatlon of unsaturated fatty acids. Phospholipid components of meats are generally rich in polyunsaturated fatty acids and hence are generally prone to autoxidatlon (27). 

Neutralization Fatty acids, phospholipids, pigments, oil insolubles, water solubles... 

Acid-catalyzed procedures typically are either boron trifluoride/methanol (BF3/ CH3OH) or hydrochloric acid/methanol (HCI/CH3OH). Many analysts use sulfuric acid instead of hydrochloric acid. Acid-catalyzed procedures are used for free fatty acids, phospholipids, or triacylglycerols, often at elevated temperatures. Although the procedures are relatively efficient at production of methyl esters, there will be some isomerization of some cis-, trans-isomers to the trans-Ztrans-isomers (136). This isomerization can be reduced by using lower temperatures, for instance 60 °C, for HCI/CH3OH or room temperature for BF3/CH3OH (137). However, under these milder conditions, some phospholipids may not be esterified (137). In addition, methoxy adducts may be formed and hydroxy fatty acids may produce artifacts. 

Refined com oil is obtained from the germ or embryo of Tea mays Linne (Fam. Gramineae), which contains nearly 50% of the fixed oil compared with 3.0-6.5% in the whole kernel. The oil is obtained from the embryo by expression and/or solvent extraction. Refining involves the removal of free fatty acids, phospholipids, and impurities decolorizing with solid adsorbents dewaxing by chilling and deodorization at high temperature and under vacuum. 

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