Phosphatidylethanolamine synthetic

B) tobacco phosphatidylcholine ( ), synthetic dioleate phosphatidylcholine ( ), tobacco phosphatidylethanolamine ( ), synthetic dipalmitate phosphatidylethanolamine (O), digalactosyldiacylglycerol ( ), tobacco PG as control ( A ). ... 

Muramyl tripeptide phosphatidylethanolamine (MTP-PE), a synthetic analogue of muramyl dipeptide and an effective systemic macrophage activator, induces a variety of cytokines such as IL-1, IL-6, and TNE, as well as PGE2 (205). Preirradiation treatment of mice using MTP-PE encapsulated in Hposomes, which can intensify radioprotective abiHty, stimulates the monocyte/macrophage system and accelerates the recovery of hemopoietic cells. 

Figure 1. Synthetic pathway for PS and PE in mammalian cells. The major steps occuring in the synthesis and interconversion of PS and PE are shown. The PS synthases condense serine with a phosphatidyl moiety derived from PC and PE. The nascent PS can be converted to PE by decarboxylation. PE can also be formed by transfer of a phosphoethanolamine moiety from CDP-ethanolamine to diacylglycerol via the Kennedy pathway. The abbreviations used are PC, phosphatidylcholine PS, phosphatidylserine PE, phosphatidylethanolamine DG, diacylglycerol PSD, phosphatidylserine decarboxylase PSS, PS synthase.

Figure 4 Design of a chemically defined diepitope liposomal anticancer vaccine. Small unilamellar liposomes (PC/PG/Chol 75/20/50 molar ratio diameter 65nm) containing 5mol% of the synthetic thiol-reactive lipopeptide adjuvant anchor Pam3CSS-Mal were reacted, at 25°C and pH 6.5, with equimolar quantities of the peptides ErbB2 (p63-71), derivatized with a CG linker at its N-terminus, and HA307-319, derivatized with a C-linker at its C-terminus. Abbreviations PC, phosphatidylcholine PE, phosphatidylethanolamine SUV, small unilamellar vesicles. Source From Refs. 11, 74.

Renin inhibitors have been found among naturally occurring phospholipids and synthetic phosphatidylethanolamine derivatives. Pepstatin (5.131), isolated from Streptomyces strains, is a pentapeptide with an acylated N-terminus and the unusual 4-amino-3-hydroxy-6-methylheptanoic acid (AHMH) residues. It is a general protease... 

Fig. 21-5, are also used for formation of both phosphatidylcholine and phosphatidylethanolamine. In both cases, the free base, choline, or ethanolamine180a b is phosphorylated with ATP. Choline phosphate formed in this manner is then converted by reaction with CTP to CDP-choline (Eq. 17-58).181 Phosphatidylcholine is formed from this intermediate1813/b while CDP-ethanolamine is used to form phosphatidylethanolamine (Fig. 21-5). These synthetic reactions occur within cell nuclei as well as on surfaces of cytoplasmic membranes.1810...

Phospholipase A2 Action. As in the case of phosphatidylcholine, the above-mentioned phospholipases will attack only the sn-3 form of naturally occurring (as well as synthetic) phosphatidylethanolamine. The products are, of course, lysophosphatidylethanolamine (1 -6>-acyl-2-lyso-.rn-glycero-3-phosphoethanolamine) and the fatty acids (liberated from the sn-2 position). The latter can be analyzed for composition and structure, as the methyl esters, by gas-liquid chromatography coupled with mass spectrometry. Usually these acyl groups are largely the unsaturated types. 

Fig. 7. The increase in surface pressure of phospholipid monolayers as a function of signal-peptide concentration for the various E. coli LamB synthetic signal sequences (from Briggs, 1986). A monolayer of egg phosphatidylethanolamine and egg phosphatidylgly-cerol (65 35) was spread from a benzene solution onto 5 mM Tris buffer, pH 7.3, yielding a hnal surface pressure of 20 dyn/cm after evaporation of the benzene. The peptide was added by injecting a concentrated solution below the lipid-water interface. The surface pressure was measured by the du Noiiy ring method with a Fisher Autotensiomat equipped with a platinum-iridium ring. The plateau values are plotted as a function of the peptide concentration for the wild-type (O), Pro— Leu pseudorevertant (A), and deletion-mutant ( ) peptides.

D. Chapman, N. F. Owens, and D. A. Walker, Physical Studies of Phospholipids. II. Monolayer Studies of Some Synthetic 2,3-diacyl-DL-phosphatidylethanolamines and Phosphatidylcholines Containing Trans Double Bonds, Biochim. Biophys. Acta 120, 148-155.(1966). 

Phospholipase B is known as monoacylphos-pholipase (lysophospholipase). Both 1-acyl and 2-acyl monoacyl derivatives of phosphatidylcholine and phosphatidylethanolamine are attacked. Unsaturated fatty acids are the preferred chains for attack (van den Bosch et al., 1968). Other synthetic compounds are also hydrolysed e.g. acyl ethylene-glycolphosphorylcholine (Dawson, 1973). Although the classic phospholipase B is prepared from Penicillium notatum, the enzyme from that source will, in fact, hydrolyse diacylphospholipids under certain conditions, and is therefore a phospholipase A (Kawasaki and Saito, 1973). 

Phospholipids are generally considered to have an antioxidant effect in foods, but this activity is confounded by the formation of reducing browning material at elevated temperatures (Chapter 9). Phosphatidylethanolamine appears to have synergistic activity in mixtures with natural tocopherols and synthetic antioxidants. This synergistic activity is often related to the metal scavenging ability of phospholipids. 

The vast majority of the stereochemical studies that have been performed to date are those of enzymes that utilize a nucleotide as a substrate. However, Bruzik and Tsai reported the synthesis of the diastereomers of phosphatidylethanolamine that are chiral by virtue of substitution with 0 and 0 (Bruzik and Tsai, 1982). Their route to the desired product involves the acid-catalyzed hydrolysis of a five-membered ring cyclic phosphoiami-date, which directly yields the ethanolamine moiety on P—N bond cleavage the steps in the synthesis are shown in Fig. 5. dearly, this synthetic strategy is relatively inflexible as to the types of phospholipids that are directly accessible, but the known abihty of phospholipase D to catalyze a facile transphosphorylation reaction (with retention of configuration) does increase the number of chiral phospholipids that can be synthesized. 

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