Phosphatidylcholine (PtdCho) and phosphatidylethanolamine (similarly to phosphatidylinositol, Ptdlns) can generate second messengers such as diacylglycerol (DAG) and phosphatidic acid, which in turn is a precursor of DAG, lysophosphatidic acid, and arachidonic acid, through three major catabolic pathways, respectively, mediated by specific phospholipases of type C (PLC) and D (PLD), acting at the two distinct phosphodiester bonds of the phospholipid headgroup and by phospholipase A2 (PLA2) in the deacylation reaction cascade .
Tumors are characterized by increased levels of palmitate-containing PtdCho, and other products of de novo fatty acid synthesis with respect to normal tissue and activation of lipid metabolism represent a well-known feature of malignant transformation (which is known by the name of lipogenic phenotype ).
DHA metabolism and choline metabolism are linked by the enzyme phosphatidylethanolamine-N-methyltransferase (PEMT) , which catalyzes de novo biosynthesis of phosphatidylcholine (PtdCho
) by methylation of PtdEtn enriched with DHA .
Compared with the balanced constitution, the contents of lactate (FA) and unsaturated fatty acid (UFA) are lower while the contents of glutamine, glucose, phosphatidylcholine (PtdCho
), and high density lipoprotein (HDL) are higher in serum of Yang deficiency constitution, and the content of creatinine is lower while the contents of lactate, DMA, citrate, and hippurate are higher in the urine of Yang deficiency constitution.
However, steady-state PtdCho
content, determined by analysis of the choline peak (Figure 3) resonating at 3.4 ppm in the [sup.1]H spectra acquired from the lipid phase of cell extracts, was not significantly increased in cells treated with Epi (1.12[+ or -] 0.23 [micro]mol/mg protein) compared with control cells (0.99 [+ or -] 0.03 [micro]mol/mg protein).
)2 and phosphatidylethanolamine (PtdEtn) comprise 40-50% and 35-45%, respectively, of the parasite's total plasma membrane phospholipid content .