Phospholipids, chemical synthesis

The new 31p-NMR results also allow us to directly establish the specificity of various phospholipases by direct product observation and should also be very useful in regiospecific chemical synthesis of phospholipids. 

Chacko, G. K. and Hanahan, D. J. (1968) Chemical synthesis of 10 (d)- and 3-0-(L)-glyceryl monoethers, diethers and derivatives glyceride, monoester phospholipids and diether phospholipids, Biochim. Biophys. Acta 164, 252-271. 

The observation that thiyl radicals are able to isomerize alkenes was first made by Walling et al. many years ago [55] and, now the addition-elimination sequence of the phenylthiyl radicals is an established methodology in fine chemical synthesis [56]. It has been utilized as key step in the synthesis of biologically active compounds, such as (-)-gloeosporone [57a], (-l-)-hitachimycin [57b] and other naturally occurring macrolides [5b], as well as for preparing non-natural isomers of phospholipids [58]. 

There is by and large no need for the chemical synthesis of many of the phospholipids that make up macromolecular lipid assemblies in cells, since these are readily available from natural sources and are purified from these by HPLC. In effect, biological syntheses of lipids dominate chemical syntheses. However, there is some value in illustrating the general method... 

Plasmalogens are a group of phosphoglycerides which are phosphorylated derivatives of 1-alk-cw-l-enyl-2-acyl-5n-glyceroL The similarity in properties between plasmalogens and the corresponding 1,2-diacyl phospholipids has made isolation procedures difficult. Moreover, chemical synthesis is made... 

We successfully used electro-deprotection reactions in the synthesis of various classes of natural compounds, such as amino acids, oligopeptides, glycoproteins, phospholipids, saccharides, polysaccharides, etc. [279-283]. Application of the method instead of chemical synthesis of oxytocin and desamino-oxytocins led, for example, to a twofold increase in the yield of these hormones with high degree of hormonal activity (joint work with the Riga s chemists [284]). 

Barenholz, Y. and Gatt, S. (1982) Sphingomyelin metabolism, chemical synthesis and physical properties, in Phospholipids (eds J.N. Hawthorne and G.B. Ansell), Elsevier, Amsterdam, pp. 129-177. 

G. D. Kini, J. R. Beadle, K. A. Aldern, K. Y. Hostetler, Propanediol Phospholipid Prodrugs of Foscarnet (PFA) Synthesis and Structure-Antiviral Activity Relationships , in Abstracts of the 211th American Chemical Society National Meeting, Division of Medicinal Chemistry , New Orleans, LA, March 24-28, 1996, Abstract No. 172. 

Chemicals such as these bind with phospholipids, inhibiting their hydrolysis by phospholipases. They can also interact with phospholipases, thus limiting the ability of the enzyme to metabolize phospholipid. Drugs, which have this structure, may also influence the synthesis of phospholipids. 

Current theories propose that the development of cell membranes accelerated early life. Enclosing chemicals responsible for replication, protein synthesis and energy generation within a confined space allows these essential life processes to occur far more frequently than they would do otherwise. Biological membranes comprise two phospholipid layers held together by interdigitation of their hydrophobic alkyl tails as shown in Fig. 5.1. They form a lamellar structure with their polar internal and external surfaces separated by a non-polar region. In their extended form each... 

For the elucidation, synthesis, chemical properties, physical chemistry, composition, and analytical determination of the various individual phospholipid structures in animal and plant sources, the reader is referred to Wittcoff (4). Schneider (14) discusses the nomenclature used for phospholipids in more detail and provides compositional data on commercial lecithins (Table 14). 

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