Choline phosphonate

The occurrence of organophosphonic acids and their derivatives has recently been reported in a wide variety of biological material. Their presence in lipids (phosphonolipids, as analogs of phospholipids) suggests participation in cell membrane structure. Alam and Bishop (1968) have reported the presence of derived aminoethyl-phosphonate in the phospholipid of human aortas. Choline phosphonate was detected in some of the aorta samples with atherosclerotic plaques and not detected in the other samples. No aminoethylphosphonate was found in the samples. 

Although the stabilizing interactions between the amino acid side chains of PLC/j, and the choline headgroup are readily apparent in the PLC fc-phosphonate inhibitor complex, it is more difficult to identify contacts between the protein and the acyl chains of the inhibitor [45]. In part this is because thermal motion in the acyl side chains, especially the sn-1 chain, renders them somewhat disordered. Consequently, the measured distances between the side chain carbons... 

Fig. 4 Lerner s group used phosphonate [3] as the hapten to raise an antibody which was capable of hydrolysing the ester [5] shown alongside it. Schultz found that naturally occurring antibodies using phosphate [4] as their antigen could hydrolyse the corresponding p-nitrophenyl choline carbonate [6]. (Those parts of haptens [3] and [4] required for antibody recognition have been emphasized with bold bonds.)...

Ri,R2 = saturated or unsaturated fatty chains X = OH, choline, ethanolamine, serine, etc., or corresponding phosphonate isos teres -configuration. 

The occurrence of the phosphonic acid analogs of ethanolamine phosphate, serine phosphate, and choline phosphate, the three major constituents of phospholipids, has been established by Kittredge et al. (1967) in the sea anemone, Anthopleura xanthogrammica. They isolated and characterized 2-methylaminoethylphosphonic acid (XXXVII) and 2-trimethylaminoethylphosphonic acid (XXXVIII). 

Phosphonic acids are formed from phosphate esters by intramolecular rearrangement (Fig. 47). Ciliatin (2-aminoethylphosphonic acid) is a constituent of phosphonocephalin, which corresponds structurally to cephalin (D 3.2.4), and is incorporated into membranes. Ciliatin may also be methylated to the iV-trimethyl derivative, which corresponds to choline. 

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