C. Tellis et al., ISOLATION, CHEMICAL CHARACTERIZATION, AND SUBCELLULAR-DISTRIBUTION OF1-O-ALKYL-2-ACETYL-SN-GLYCEROL IN TETRAHYMENA-PYRIFORMIS CELLS, Journal of Biochemistry, 119(4), 1996, pp. 823-827
1-O-Hexadecyl-2-acetyl-sn-glycerol, the immediate precursor of platele
t-activating factor (PAF) in its de nova formation, was detected in th
e protozoon Tetrahymena pyriformis. It was purified from the total lip
id extract by TLC, after successive developments in two different solv
ent systems. Characterization was assessed by (a) gas-liquid chromatog
raphy with electron capture detection, and (b) gas chromatography comb
ined with mass spectrometry in selected ion monitoring mode, after der
ivatization with heptafluorob utyric acid anhydride and tert-butyldime
thylchlorosilane/imidazole respectively. Its quantity was found to be
0.1 nmol/10(7) cells from the CC-MS, using authentic alkylacetylglycer
ol as external standard, Cell fractionation revealed that alkylacetylg
lycerol is located exclusively in the microsomal fraction of the proto
zoon. Previously, we have reported the occurrence of PAF in the micros
omal fraction, as well as a dithiothreitol-insensitive CDP-choline: ch
olinephosphotransferase activity that utilizes exogenous alkylacetylgl
ycerol as substrate in the mitochondrial and microsomal fractions. The
above findings indicate that PAF can be formed in the cell by the de
novo pathway.