Localization of an alkyl-acetyl-glycerol-CDP-choline: cholinephosphotransferase activity in submitochondrial fractions of Tetrahymena pyriformis.
Tetrahymena pyriformis contains platelet-activating factor (PAF) as a minor lipid, which is biosynthesized de novo. A dithiothreitol-insensitive CDP-choline:cholinephosphotransferase (AAG-CPT), which utilizes alkyl-acetyl-glycerol as a substrate, had been detected in both the mitochondrial and microsomal fractions of the protozoan. In the present report, localization of this enzyme in submitochondrial fractions was studied. Cell fractionation was evaluated with enzyme and morphological markers. In this respect, succinate dehydrogenase, NADPH:cytochrome c reductase, glucose-6-phosphatase, alkaline phosphatase, monoaminoxidase, and cytochrome c oxidase activities were investigated. In the presence of antimycin A, mitochondrial activity of NADPH-cytochrome c reductase, was increased, while the microsomal one was reduced. Cardiolipin was distributed in the inner mitochondrial membrane. Alkaline phosphatase was found exclusively in the cytosol of the protozoan. The main portion of the dithiothreitol-insensitive AAG-CPT was localized in the inner mitochondrial membrane. Our data indicate that mitochondria are able to produce PAF, which might be associated with their function.
Tellis
Constantinos
C
Laboratory of Biochemistry, Chemistry Department, School of Science, University of Ioannina, Ioannina, Greece.
Pantazi
Despoina
D
Ioachim
Elli
E
Galani
Vasiliki
V
Lekka
Marilena E
ME
D000818:Animals; D002308:Cardiolipins / Q000378:metabolism*; D002458:Cell Fractionation; D003600:Cytosol / Q000201:enzymology / Q000648:ultrastructure; D002798:Diacylglycerol Cholinephosphotransferase / Q000378:metabolism*; D008861:Microsomes / Q000201:enzymology / Q000648:ultrastructure; D010972:Platelet Activating Factor / Q000378:metabolism*; D013367:Submitochondrial Particles / Q000201:enzymology* / Q000648:ultrastructure; D013769:Tetrahymena pyriformis / Q000201:enzymology* / Q000648:ultrastructure
D002308:Cardiolipins; D010972:Platelet Activating Factor; D002798:Diacylglycerol Cholinephosphotransferase