1-O-alkyl-2-acetyl-sn-glycero-3-phosphate : phosphohydrolase activity in Tetrahymena pyriformis

 
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2000 (EN)
1-O-alkyl-2-acetyl-sn-glycero-3-phosphate : phosphohydrolase activity in Tetrahymena pyriformis (EN)

Tellis, C. (EN)

Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείας (EL)
Tellis, C. (EN)

Within the frame of the de novo formation of Platelet-Activating Factor in Tetrahymena, the occurrence as well as the properties of a lipid phosphate phosphohydrolase activity catalyzing the dephosphorylation of 1-O-alkyl-2-acetyl-sn-glycero-3-phosphate was investigated. The activity was distributed in all the membrane fractions of the cell and in the cytosol. It showed preference for acyl-acetyl-sn-glycero-phosphate as well, and at a much lower level, for dipalmitoyl-glycero-phosphate. Mg2+ and Ca2+ caused a dose-dependent inhibition, while F-, EDTA and EGTA had no effect. The enzymic activity was linear for at least up to 60 min incubation time and up to 150 mu g protein. Microsomal activity exhibited two optimal pH areas, around 7.0 and 9.0, while mitochondrial activity showed one peak, at pH 7.0. Acyl-GP, acyl-acetyl-GP and alkyl-GP could replace alkyl-acetyl-GP in significant rates, while dipalmitoyl-GP, beta-GP, fructose-6-GP, p-nitrophenylphosphate, creatine phosphate or ATP had no effect. Side phospholipose A(2) and C activities were also detected. Taking into account the presence of PAF and alkylacetylglycerol in the protozoan as well as the presence of a dithiothreitol- insensitive CDP-choline:cholinephosphotransferase activity that converts alkylacetylglycerol to PAF, we suggest that the present phosphohdrolase activity may be involved in the de novo production of PAF within Tetrahymena. (EN)

alkyl-acetyl-glycerophosphate : phosphohydrolase paf (EN)

Πανεπιστήμιο Ιωαννίνων (EL)
University of Ioannina (EN)

Journal of Eukaryotic Microbiology (EN)

2000

<Go to ISI>://000086049500003

Wiley-Blackwell (EN)



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