Phospholipid classification

Fig. (7). Phospholipid classification according to the polar head group.

Phosphine(s), chirality of, 314 Phosphite, DNA synthesis and, 1115 oxidation of, 1116 Phospholipid, 1066-1067 classification of, 1066 Phosphopantetheine, coenzyme A from. 817 structure of, 1127 Phosphoramidite, DNA synthesis and, 1115 Phosphoranc, 720 Phosphoric acid, pKa of, 51 Phosphoric acid anhydride, 1127 Phosphorus, hybridization of, 20 Phosphorus oxychloride, alcohol dehydration with. 620-622 Phosphorus tribromide, reaction with alcohols. 344. 618 Photochemical reaction, 1181 Photolithography, 505-506 resists for, 505-506 Photon, 419 energy- of. 420 Photosynthesis, 973-974 Phthalic acid, structure of, 753 Phthalimide, Gabriel amine synthesis and, 929... 

Phospholipid Kinases. Figure 2 Classification of phosphoinositide 3-kinases. 

Liposomes are formed due to the amphiphilic character of lipids which assemble into bilayers by the force of hydrophobic interaction. Similar assemblies of lipids form microspheres when neutral lipids, such as triglycerides, are dispersed with phospholipids. Liposomes are conventionally classified into three groups by their morphology, i.e., multilamellar vesicle (MLV), small unilamellar vesicle (SUV), and large unilamellar vesicle (LUV). This classification of liposomes is useful when liposomes are used as models for biomembranes. However, when liposomes are used as capsules for drugs, size and homogeneity of the liposomes are more important than the number of lamellars in a liposome. Therefore, "sized" liposomes are preferred. These are prepared by extrusion through a polycarbonate... 

In addition to this classification of cellular function by domain cooccurrence, analyses of domain combinations can also be used to improve the prediction of a protein s function. The RhoGEF domain, for example, is invariably found N-terminally to a PH domain. The cooccurrence of these two domains appears to be correlated with altered electrostatic potential, thereby resulting in prevention of the PH domain from binding phospholipids (Blomberg et al., 1999). As this is a frequent function of the PH domain, the determination of a protein s domain architecture can assist in discounting a specific predicted function. 

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. 

Table 1.6 The classification of phospholipids according to the nature of their Ri group. R groups have long hydrocarbon chains, the same as those found in fatty acids. The R groups in a particular molecule do not have to have the same structures...

The polar lipid composition of extreme halophiles appears to be correlated with their taxonomic classification on the level of the genera so far distinguished [4,5,10,32, 50-52,54] Halobacterium, Haloarcula, Haloferax, Halococcus, Natronobacterium and Natronococcus (Table 1). All of these genera were found to contain C2o-C2o-archaeol PGP-Me (4A) as the major phospholipid, C2o-C2o-archaeol PG (3) and PGS (5) as minor phospholipids, and small to trace amounts of archaeol PA (6) [5,10,11,32,40] (see Table 1), with the following exceptions (a) PGS is characteristically absent... 

For a classification of phospholipids and the structure of other phospholipid classes, the reader is referred to K.P. Strickland, in Form and Function of Phospholipids, G.B. Ansell, J. Hawthorne and R.M.C. Dawson, Eds., Elsevier (1975) 9. 

Antilipemics lower lipid levels (Table 19.4). Lipids are composed of cholesterol, triglycerides, and phospholipids, which are bound to lipoproteins (Table 19.5) that transport lipids throughout the body. There are three classifications of lipoproteins ... 

Fig. 5.28 Classification ofthe phospholipases and the reaction of phospholipase C. a) Cleavage specificity of phospholipases Al, A2, C and D. b) Cleavage of inositol-containing phospholipids by phospholipase C. In a reaction of particular importance for signal transduction, phospholipase C (PL-C) catalyzes the cleavage of phosphatidyl inositol-4, 5-bisphosphate (Ptdlns(4,5)P2) into the messenger substances diacylglycerol and inositol 1,4,5-triphosphate (lns(l,4,5)P3).

Myelin is approximately 75% lipid and 25% protein. Carbohydrate residues are associated with both the lipid and the protein components of myelin. High proportions of cholesterol, phospholipid, and glycolipid are found in the lipid fractions. Phospholipids include ethanolamine phosphatides, phosphatidylserine, and phosphatidylinositol glycolipids include both neutral (cerebroside, sulfatide, galactosyldiglyceride) and polar (gangliosides, especially GMj and GMJ lipids. A classification and discussion of the metabolism of brain lipids is beyond the scope of this article readers are referred to Lajtha (1969), Davison (1968), Awasthi and Srivastava (1980), and Suzuki (1981). 

Cholesterol, which is largely insoluble in aqueous m a, travels through the blood circulation in the form of Upoprotein complexes. The plasma lipoproteins are a family of globular particles that share common structural features. A core of hydrophobic lipid, principally triacylglycerols (triglycerides) and cholesterol esters, is surrounded by a hydrophilic monolayer of phospholipid and protein (the apolipoproteins) [1-3]. Lipid-apolipoprotein interactions, facihtated byi amphi-pathic protein helices that segregate polar from nonpolar surfaces [2,3], provide the mechanism by which cholesterol can circulate in a soluble form. In addition, the apolipoproteins modulate the activities of certain enzymes involved in Upoprotein metabolism and interact with specific cell surface receptors which take up Upopro-teins by receptor-mediated endocytosis. Differences in the Upid and apoUpoprotein compositions of plasma Upoproteins determine their target sites and classification based on buoyant density. 

Classify lipids both into the large classifications (such as simple lipids, complex lipids, phospholipids, etc.) and into the more specific classifications (such as waxes, triglycerides, cephalins, lecithins, steroids, prostaglandins, terpenes, etc.). 

Classification Phospholipids Formula CH20RiCH0R2CH20P(0)(0H)0R3 Properties YIsh. amorphous char, odor and taste insol. in water, acetone sol. in chloroform, ether si. sol. in alcohol dens. 1.00 Uses Medicine biochemical research diagnostic use clinical reagent (liver function test) skin conditioner in cosmetics promotes blood clotting in after-shave prods. Manuf./Distrib. Fluka http //www.sigma-aldrich.com] Sigma... 

Koch et al. determined total cholesterol, phospholipids, and fatty acids in CSF samples from 216 individuals in order to establish the lipid and apo-lipoprotein levels in Cerebrospinal Fluid (CSF) in a large group of individuals, on the basis of which a classification of CSF lipoproteins was made. The cholesterol and phospholipids are measured enzymatically by fluorometric detection of the reaction products. Earlier work had shown reduced levels of cholesterol, phospholipids, and free fatty acids in Cerebrospinal Fluid (CSF) of Alzheimer disease patients. Urine levels of F2-isoprostanes or their major metabolite were not significantly different between Alzheimer s disease patients and controls. In addition, urine and CSF F2-isoprostane levels in Alzheimer s disease patients did not correlate. These results indicate that plasma and urine F2-isoprostanes and F2-neuroprostanes do not accurately reflect central nervous system levels of these biomarkers and are not reproducibly elevated in body fluids outside of the central nervous system in Alzheimer s disease patients. 

Classification and Structure M.l. can be classified structurally in several different ways The present classification (Fig.l) divides them into phospholipids, glycolipids and Sterols (see). The phospholipids are divided into glycerophospholipids and sphingophos-pholipids, the ycolipids into glyceroglycolipids and sphingoglycolipids each of these subclasses is then divided into subsubclasses Phospholipids and glycolipids can be described as acylated-M.I. because they have at least one fatty acyl residue (R.C = O where R is a hydrocarbon chain) in their structure in this they differ from sterols which occur in biomembranes in non-acylated form. 

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