Phosphate diesters with choline

The cephalins have structure similar to that of the lecithins but with the radical —OCH2CH2NH2 in place of the cholyl radical that is, they are the glycerophosphate esters of the alcohol j8-aminoethanol, HO(CH2)2 NH2. The sphingomyelins are the phosphate diesters of choline and the complex alcohol sphingosine, H3C(CH2)i2CH=CHCH(OH)CH(NH2) CH2OH. The cephalins and sphingomyelins are found in the brain and nerves. ... 

Phosphate diester bonds are produced by a specific, group-transferring coenzyme, cytidine diphosphate (cf. Chapt. VI-5). A hydroxyl compound, here in our diagram it is choline, is phosphorylated initially and then raised to a high potential for group transfer by the reaction with cytidine triphosphate (CTP) pyrophosphate is split off in the process. 

The final region from -2.00 to 0.00 ppm is attributed to diester phosphates such as RNA, DNA, nucleotide fragments, and phosphatidyl compounds. Signals occur in this region for both DNA and phosphatidyl choline in a concentrated humic matrix with FeEDTA present (Figure 11). 3IP FT-NMR evidence supporting the presence of DNA is provided by the spectrum of a sample that has been oxidized by alkaline bromination (Figure 12). 

Nonspecific Phosphoesteroses. These enzymes cleave a variety of phosphoric acid derivatives, even synthetic substrates and lecithins (diesters of phosphoric acid with glycerol and choline). Such enzymes occur among other places in snake venom, and in the intestinal mucosa. Snake venom phosphatases specifically split 3 -phos-phate bonds, giving rise to 5 -monophosphates, whereas chemical hydrolysis yields a mixture of the 2 - and 3 -monophosphates. Free 3 -phosphate groups (the monoesters) are inhibitory in the enzymic reaction. 

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