Disease relevance of 2-hydroxyethyl-trimethyl-phosphonium

• C6 rat glioma cells, C3H10T12 fibroblasts and rat hepatocytes were permeabilized with Staphylococcus aureus alpha-toxin, and the incorporation of the radiolabelled precursors choline, phosphocholine (P-choline), ethanolamine and phosphoethanolamine (P-EA) into PC and PE were measured both at high and low Ca2+ concentrations [1].
• There was a 70% decrease in P-choline in brown cataracts but no significant change from normal in non-brown cataracts [2].

High impact information on 2-hydroxyethyl-trimethyl-phosphonium

• The total accumulation of P-choline over a 10-h period exhibited Michaelis-Menten kinetics [3].
• Addition of choline to the perfusate of compressed sycamore cells monitored by 31P NMR spectroscopy resulted in a dramatic accumulation of P-choline in the cytoplasmic compartment containing choline kinase and not in the vacuole [3].
• Release of P-choline and choline from purified rat plasma membrane preparations was increased by GTP and its less hydrolyzable analogues, whereas other nucleotide triphosphates had little or no effect [4].
• The results suggest that the P-choline groups on the surface of liposomes play an important role in the binding to PCBP and this may provide a possible explanation of the effect of PCBP on the Ca2+-dependent heparin-lipoprotein precipitation reaction [5].
• The results indicate that in contrast to the high deltaG0obs for the hydrolysis of the ester bond of acetylcholine, the deltaG0obs for the hydrolysis of the ester bond of P-choline is quite low, among the lowest known for phosphate ester bonds of biological interest [6].

Chemical compound and disease context of 2-hydroxyethyl-trimethyl-phosphonium

• Phosphorylcholine (P-choline), and phosphorylethanolamine (P-ethanolamine) are among the organic phosphate compounds that decrease in concentration in some cataracts and in lenses that have been subjected to cataractogenic osmotic or oxidative stresses [7].

Biological context of 2-hydroxyethyl-trimethyl-phosphonium

• Significance of the present study rests on the possibility that the mechanism of action of CRP in cellular metabolism might be related to the production of DAG and P-choline known to have roles respectively in signal transduction and growth factor stimulated DNA synthesis [8].
• Rabbit CRP, even though a P-choline binding protein, was found to have no inhibitory effect on the serum lipoprotein-heparin-Ca2+ precipitation reaction [9].

Anatomical context of 2-hydroxyethyl-trimethyl-phosphonium

• ATP and ADP, in concentrations ranging from 1-100 microM, increased the release of [3H]choline and [3H]phosphorylcholine (P-choline) from bovine aortic endothelial cells (BAEC) prelabelled with [3H]choline [10].
• Two to 7 days postlesion, P-choline levels were elevated 48% in the hippocampus ipsilateral to the entorhinal cortex lesion, but not in the contralateral hippocampus or cerebral cortex [11].
• Immunocytochemical study of the relations of acetylcholinesterase, enkephalin-, substance P-, choline acetyltransferase- and calcitonin gene-related peptide-immunoreactive structures in the ventral horn of rat spinal cord [12].

Associations of 2-hydroxyethyl-trimethyl-phosphonium with other chemical compounds

• Prior treatment of plasma membranes with cholera toxin or prior injection of animals with islet-activating protein did not affect the stimulation of P-choline plus choline release either by GTP gamma S alone or by GTP gamma S plus ATP [4].
• Osmotic stress induced by incubation with 30 mM xylose caused increased P-choline and P-ethanolamine efflux from the lenses, but had little effect on the rate of hydrolysis of these compounds [7].
• Oxidative stress from singlet oxygen (generated by rose bengal and light) also increased lenticular P-choline efflux three to four-fold, with minimal effects on hydrolysis, and the increased efflux was accompanied by a decrease in the P-choline concentration [7].

Analytical, diagnostic and therapeutic context of 2-hydroxyethyl-trimethyl-phosphonium

• However, when 100 microM inorganic phosphate was present in the perfusion medium, externally added Pi was preferentially used to sustain P-choline synthesis [3].
• Human serum appears to lack P-choline-binding protein, since (a) the affinity column did not adsorb any such protein, (b) P-choline had no effect on the Ca2+-heparin-serum lipoprotein precipitation reaction, and (c) an immunodiffusion test against the antiserum was negative [13].
• The metabolism and concentration of P-choline has been shown to change in animal models of cataract, especially in oxidatively or osmotically stressed rat lenses [2].

References