Ethanolamine phosphate

A bacterial phosphatidylinositol specific phospholipase C (PI-PLC) had been available for many years before it was demonstrated to strip a number of membrane-bound proteins from eukaryotic cell surfaces [1], Such proteins are anchored by a PI moiety in which the 6 position of inositol is glycosidically linked to glucosamine, which in turn is bonded to a polymannan backbone (Fig. 3-10). The polysaccharide chain is joined to the carboxyl terminal of the anchored protein via amide linkage to ethanolamine phosphate. The presence of a free NH2 group in the glucosamine residue makes the structure labile to nitrous acid. Bacterial PI-PLC hydrolyzes the bond between DAG and phosphati-dylinositols, releasing the water-soluble protein polysac charide-inositol phosphate moiety. These proteins are tethered by glycosylphosphatidylinositol (GPI) anchors. 

This enzyme [EC 2.7.7.14], also referred to as ethanol-amine-phosphate cytidylyltransferase and phosphoryl-ethanolamine transferase, catalyzes the reaction of CTP with ethanolamine phosphate to produce CDP-ethanol-amine and pyrophosphate. 

ETHANOLAMINE N-METHYLTRANSEERASE Ethanolamine phosphate cytidylyltransferase, CTP ETHANOLAMINEPHOSPHATE CYTIDYLYLTRANSFERASE... 

Fig. 5. The reaction of ethanolamine-phosphate cytidylytransferase with substrates and analogues. Reaction 1 shows the normal reaction of the enzyme with ethanolamine phosphate (2-aminoethyl phosphate), which is part of the route of phospholipid synthesis. The alternative reaction with 2-aminoethylphosphonate, in parentheses, is used by some marine organisms to insert a C—P bond into their phospholipids. Reaction 2 shows the futile cycle obtained with 2-aminoethylarsonate (59). The symbol -P signifies -P03H2 and its ionized forms, and -P- signifies -P(0)(0H)- and its ionized form (61).

Synthesis of PE and PC from preexisting choline and ethanolamine These synthetic pathways involve the phosphorylation of choline or ethanolamine by kinases, followed by conversion to the activated form, CDP-choline or CDP-ethanolamine. Finally, choline-phosphate or ethanolamine-phosphate is transferred from the nucleotide (leaving CMP) to a molecule of diacylglycerol (see Figure 17.5). 

Fig. 6. Structures of the LPS-derived oligosaccharides and OPS containing legionaminic acid (Leg). [D-a-D-Hep and L-a-D-Hep, D-glycero- and L-glycero-a-D-manno-heptose Kdo, 3-deoxy-D-manno-oct-2-ulosonic acid Fuc4NR3Hb, 4-[(R)-3-hydroxybutanamido]-4,6-dideoxygalactose Ala, L-alanyl Cm, carbamoyl PEtn, ethanolamine phosphate R is acetyl in some repeating units and (S)-3-hydroxybutanoyl in the others.]...

EtP, ethanolamine phosphate) (b) a myristoylated protein (c) a prenylated protein (d) a palmitoylated protein. 

Employing the same strategy and precursors as outlined above (Sects. 2.3 and 4), the phosphorylated heptoside disaccharides 38-40 [10] (Fig. 4), corresponding to Salmonella core structures (Fig. 1), were synthesised. A 7-0-phosphorylated structure (41) of the same disaccharide, corresponding to a Neisseria structure, has also been synthesised by van Boom [11]. This derivative was synthesised as the ethanolamine phosphate derivative and the oligosaccharide part was linked via a spacer to a peptide part, altogether re-... 

Phospholipids may consist of a backbone of glycerol esterified with two fatty acids and one molecule of choline phosphate in the position. Tn other phospholipids, the 3 position may be occupied by a molecule of ethanolamine phosphate, serine phosphate, or inositol phosphate. A phospholipid containing choline phosphate is called phosphatidylcholine one containing ethanolamine phosphate is called phosphatidylethanolamine. Generally, the fatty acids esterified as triglycerides contain up to one double bond, whereas those esterified as phos-... 

P19. Peterson, D. W., Lilyblade, A. L., and Lyon, J., Serine-ethanolamine phosphate, taurine and free amino acids of muscle in hereditary muscular dystrophy of the chicken. Proc. Soc. Exp. Biol. Med. 113, 798-802 (1963). 

The synthesis of glycosylphosphatidylinositol (GPI) anchors of proteins, including Thy-1 of neurons and lymphocytes, is primarily carried out within the lumen of the rough endoplasmic reticulum. The anchor consists of a phosphatidylinositol-glucosamine-mannosey-ethanolamine phosphate core that is linked to the a-carboxyl of the carboxyterminal amino acid of a protein (Figure 16-12). This addition takes place within minutes of... 

A degree of organ specificity for substrate is to be expected. Thus, a substrate preference known is the ability of intestinal alkaline phosphatase to hydrolyze o-carboxyphenylphosphate more rapidly than other substrates (Fll, F13). Further, placental alkaline phosphatase is stated to hydrolyze p-nitrophenyl phosphate less rapidly than j8-glycerophos-phate (SI). Although ethanolamine phosphate is hydrolyzed preferentially by rat liver alkaline phosphatase, such a preference was missing from human liver preparations (Fll). 

H6. Harris, H., and Robson, E. B., A genetical study of ethanolamine phosphate excretion in hypophosphatasia. Ann. Human Genet. 23, 421-433 (1959). 

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