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Choline phosphatidylcholine

Glycerophospholipids are used for membrane synthesis and for producing a hydrophilic surface layer on lipoproteins such as VLDL. In cell membranes, they also serve as a reservoir of second messengers such as diacylglycerol, inositol 1,4,5-triphosphate, and arachidonic acid. Their structure is similar to triglycerides, except that the last fatty acid is replaced by phosphate and a water-soluble group such as choline (phosphatidylcholine, lecithin) or inositol (phosphatidyl-inositol). [Pg.210]

Zeisel, S. H., Char, D., and Shepard, M. F. (1986)- Choline, phosphatidylcholine and sphingomyelin in human and bovine milk and infant formulas, /. Nutr. 116,50-56,... [Pg.378]

One-carbon methyl donors for tetrahydrofolate and SAM Glycine, serine, histidine, methionine Most cells, but highest in liver Choline, phosphatidylcholine, purine and pyrimidine synthesis, inactivation of waste metabolites and xenobiotics through methylation. [Pg.850]

Figure 1 Hydrolysis of ester linkages in glvcerophospholipids bv phospholipases Ai. A . C and D. The fatty acid at the sn-1-position (Ri) is usually saturated while that at the sn-2-position (R2) is unsaturated. R3 varies in different phospholipids and could be choline (phosphatidylcholine), ethanolamine (phosphatidylethanolamine), serine (phospha-tidylserlne), myoinositol (phosphatidylinositol), myoino-sitol-4-monophosphate (phosphatidylinositol-4-monophosphate) or myoinositol-4,5-blsphosphate (phosphatidylinositol-4,5-bisphosphate). In phosphatidic acid, R3 is a hydrogen atom. Figure 1 Hydrolysis of ester linkages in glvcerophospholipids bv phospholipases Ai. A . C and D. The fatty acid at the sn-1-position (Ri) is usually saturated while that at the sn-2-position (R2) is unsaturated. R3 varies in different phospholipids and could be choline (phosphatidylcholine), ethanolamine (phosphatidylethanolamine), serine (phospha-tidylserlne), myoinositol (phosphatidylinositol), myoino-sitol-4-monophosphate (phosphatidylinositol-4-monophosphate) or myoinositol-4,5-blsphosphate (phosphatidylinositol-4,5-bisphosphate). In phosphatidic acid, R3 is a hydrogen atom.
Very little information is available on the choline content of foods. ° Most choline in foods is found in the form of phosphatidylcholine. Milk, eggs, liver, and peanuts are especially rich in choline. Phosphatidylcholine also known as lecithin contains about 13% choline by weight. [Pg.272]

Reactions of heterolipids are generally similar to those of other lipids, but reactions of bound phosphoric acid are specific to heterolipids. Phospholipids are hydrolysed by various phospholipases an overview of which is given in Table 3.47 and the mechanism of their action is shown in Figure 3.89. Phosphatidylcholine is a demanded product and its concentration in lecithin can be increased by enzymatically controlled interesterification after adding choline. Phosphatidylcholine can also be produced directly from diacylglycerols or phosphatidic acids using immobilised enzymes. [Pg.204]

Phosphatidylcholine is an important component of cell membranes but cell mem branes are more than simply lipid bilayers Although their composition varies with their source a typical membrane contains about equal amounts of lipid and protein and the amount of cholesterol m the lipid fraction can approximate that of phosphatidylcholine The lipid fraction is responsible for the structure of the membrane Phosphatidyl choline provides the bilayer that is the barrier between what is inside the cell and what IS outside Cholesterol intermingles with the phosphatidylcholine to confer an extra measure of rigidity to the membrane... [Pg.1078]

The identity of the moiety (other than glycerol) esterified to the phosphoric group determines the specific phosphoHpid compound. The three most common phosphoHpids in commercial oils are phosphatidylcholine or lecithin [8002-45-5] (3a), phosphatidylethanolamine or cephalin [4537-76-2] (3b), and phosphatidjlinositol [28154-49-7] (3c). These materials are important constituents of plant and animal membranes. The phosphoHpid content of oils varies widely. Laurie oils, such as coconut and palm kernel, contain a few hundredths of a percent. Most oils contain 0.1 to 0.5%. Com and cottonseed oils contain almost 1% whereas soybean oil can vary from 1 to 3% phosphoHpid. Some phosphoHpids, such as dipaLmitoylphosphatidylcholine (R = R = palmitic R" = choline), form bilayer stmetures known as vesicles or Hposomes. The bdayer stmeture can microencapsulate solutes and transport them through systems where they would normally be degraded. This property allows their use in dmg deHvery systems (qv) (8). [Pg.123]

Fig. 1. Chemical stmcture of phosphatidylcholine (PC) (1) and other related phosphohpids. R C O represents fatty acid residues. The choline fragment may be replaced by other moieties such as ethanolamine (2) to give phosphatidylethanolamine (PE), inositol (3) to give phosphatidylinositol (PI), serine (4), or glycerol (5). IfH replaces choline, the compound is phosphatidic acid (6). The corresponding lUPAC-lUB names ate (1), l,2-diacyl-t -glyceto(3)phosphocholine (2), l,2-diacyl-t -glyceto(3)phosphoethanolamine (3), 1,2-diacyl-t -glyceto(3)phosphoinositol (4), 1,2-diacyl-t -glyceto(3)phospho-L-serine and (5), l,2-diacyl-t -glyceto(3)phospho(3)-t -glycetol. Fig. 1. Chemical stmcture of phosphatidylcholine (PC) (1) and other related phosphohpids. R C O represents fatty acid residues. The choline fragment may be replaced by other moieties such as ethanolamine (2) to give phosphatidylethanolamine (PE), inositol (3) to give phosphatidylinositol (PI), serine (4), or glycerol (5). IfH replaces choline, the compound is phosphatidic acid (6). The corresponding lUPAC-lUB names ate (1), l,2-diacyl-t -glyceto(3)phosphocholine (2), l,2-diacyl-t -glyceto(3)phosphoethanolamine (3), 1,2-diacyl-t -glyceto(3)phosphoinositol (4), 1,2-diacyl-t -glyceto(3)phospho-L-serine and (5), l,2-diacyl-t -glyceto(3)phospho(3)-t -glycetol.
Acetylcholine Precursors. Early efforts to treat dementia using cholinomimetics focused on choline [62-49-7] (12) supplement therapy (Fig. 3). This therapy, analogous to L-dopa [59-92-7] therapy for Parkinson s disease, is based on the hypothesis that increasing the levels of choline in the brain bolsters acetylcholine (ACh) synthesis and thereby reverses deficits in cholinergic function. In addition, because choline is a precursor of phosphatidylcholine as well as ACh, its supplementation may be neuroprotective in conditions of choline deficit (104). [Pg.96]

In nutrition, the most important function of choline appears to be the formation of lecithin (phosphatidylcholine) (2) and other cb oline-containing pho sphohpids. [Pg.100]

Figure 1 Chemical structure and space-filling representation of a phosphatidylcholine, DPPC. Different parts of the molecule are referred to by the labels at the left together the choline and phosphate are referred to as the headgroup, which is zwitteriomc. In the space-filling model, H atoms are white, O and P gray, and C black. (From Ref. 55.)... Figure 1 Chemical structure and space-filling representation of a phosphatidylcholine, DPPC. Different parts of the molecule are referred to by the labels at the left together the choline and phosphate are referred to as the headgroup, which is zwitteriomc. In the space-filling model, H atoms are white, O and P gray, and C black. (From Ref. 55.)...
One important phospholipid is phosphatidylcholine, also called lecithin. Phosphatidylcholine is a mixture of diesters of phosphoric acid. One estei function is derived from a diacylglycerol, whereas the other is a choline [—OCH2CH2N(CH3)3] unit. [Pg.1078]

Phospholipid (Section 26.4) Adiacylglycerol bearing a choline-phosphate head group. Also known as phosphatidylcholine. [Pg.1291]

Phosphatidylethanolamine synthesis begins with phosphorylation of ethanol-amine to form phosphoethanolamine (Figure 25.19). The next reaction involves transfer of a cytidylyl group from CTP to form CDP-ethanolamine and pyrophosphate. As always, PP, hydrolysis drives this reaction forward. A specific phosphoethanolamine transferase then links phosphoethanolamine to the diacylglycerol backbone. Biosynthesis of phosphatidylcholine is entirely analogous because animals synthesize it directly. All of the choline utilized in this pathway must be acquired from the diet. Yeast, certain bacteria, and animal livers, however, can convert phosphatidylethanolamine to phosphatidylcholine by methylation reactions involving S-adenosylmethionine (see Chapter 26). [Pg.821]

FIGURE 25.19 Diacylglycerol and CDP-diacylglycerol are the principal precursors of glycerolipids in eukaryotes. Phosphatidylethanolamine and phosphatidylcholine are formed by reaction of diacylglycerol with CDP-ethanolamine or CDP-choline, respectively. [Pg.822]

Phosphatidylethanolamine (cephalin) and ph os-phatidylserine (found in most tissues) differ from phosphatidylcholine only in that ethanolamine or serine, respectively, replaces choline (Figure 14-8). [Pg.115]

Figure 24-2. Biosynthesis of triaq/lglycerol and phospholipids. ( , Monoacylglycerol pathway (D, glycerol phosphate pathway.) Phosphatidylethanolamine may be formed from ethanolamine by a pathway similar to that shown for the formation of phosphatidylcholine from choline. Figure 24-2. Biosynthesis of triaq/lglycerol and phospholipids. ( , Monoacylglycerol pathway (D, glycerol phosphate pathway.) Phosphatidylethanolamine may be formed from ethanolamine by a pathway similar to that shown for the formation of phosphatidylcholine from choline.
There is also inside-outside (transverse) asymmetry of the phospholipids. The choline-containing phospholipids (phosphatidylcholine and sphingomyelin) are located mainly in the outer molecular layer the aminophospholipids (phosphatidylserine and phos-phatidylethanolamine) are preferentially located in the inner leaflet. Obviously, if this asymmetry is to exist at all, there must be limited transverse mobility (flip-flop) of the membrane phospholipids. In fact, phospholipids in synthetic bilayers exhibit an extraordinarily slow rate of flip-flop the half-life of the asymmetry can be measured in several weeks. However, when certain membrane proteins such as the erythrocyte protein gly-cophorin are inserted artificially into synthetic bilayers, the frequency of phospholipid flip-flop may increase as much as 100-fold. [Pg.420]

Choline-containing phospholipids Potassium iodide-bismuth subnitrate (phosphatidylcholine and Dragendorff reagent... [Pg.316]

Transversely, mammalian biomembranes exhibit a general pattern for preferential localization of choline-containing phospholipids [such as phosphatidylcholine (PC) and... [Pg.814]

The second synthetic route involves activation of an alcohol (for example, choline) to produce CDP-choline. The latter participates in the transfer of choline onto diglyceride to form phosphatidylcholine. [Pg.206]

Ethanolamine Choline HOCH2CH2NHj HOCH2CH2N+(CH3)3 Phosphatidylethanolamine Phosphatidylcholine also called Lecithin PE PC... [Pg.36]


See other pages where Choline phosphatidylcholine is mentioned: [Pg.20]    [Pg.3]    [Pg.65]    [Pg.20]    [Pg.317]    [Pg.1702]    [Pg.477]    [Pg.87]    [Pg.176]    [Pg.1140]    [Pg.564]    [Pg.111]    [Pg.323]    [Pg.20]    [Pg.3]    [Pg.65]    [Pg.20]    [Pg.317]    [Pg.1702]    [Pg.477]    [Pg.87]    [Pg.176]    [Pg.1140]    [Pg.564]    [Pg.111]    [Pg.323]    [Pg.1078]    [Pg.1078]    [Pg.1078]    [Pg.246]    [Pg.279]    [Pg.199]    [Pg.358]    [Pg.104]    [Pg.156]    [Pg.448]    [Pg.191]    [Pg.270]    [Pg.56]   
See also in sourсe #XX -- [ Pg.361 ]




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