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

Tellis, C./ Lekka, M. E.

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.
Institution and School/Department of submitter: Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείας
Keywords: alkyl-acetyl-glycerophosphate : phosphohydrolase paf,phosphatidate phosphohydrolase,phospholipase a(2),phospholipase c,phospholipid biosynthesis,platelet-activating-factor,phosphatidate phosphohydrolase,rat-liver,subcellular-distribution,biosynthesis,fractions,purification,yeast,cells,assay
URI: http://olympias.lib.uoi.gr/jspui/handle/123456789/10356
ISSN: 1066-5234
Link: <Go to ISI>://000086049500003
Publisher: Wiley-Blackwell
Appears in Collections:Άρθρα σε επιστημονικά περιοδικά ( Ανοικτά)

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