title: A PAF-acetylhydrolase activity in Tetrahymena pyriformis cells.
abstract: Our study provides evidence for the existence of an acylhydrolase activity in Tetrahymena pyriformis cells, capable of hydrolyzing the sn-2 ester bond of the PAF molecule. This activity is mainly distributed in the microsomal fraction (76.5% of total) and has properties similar to the mammalian PAF-acetylhydrolase since it is Ca(2+)-independent, acid-labile, is inhibited by DFP and PMSF but it is not affected by egg yolk phosphatidylcholine. This microsomal acylhydrolase has apparent Km and Vmax values of 1.56 microM and 373 pmols.mg.min respectively. This is the first report of the existence of a PAF-acetylhydrolase activity in a non-mammalian cell.
authors.affiliation: Department of Chemistry, University of Ioannina, Greece.
authors.forename: A D
authors.initials: AD
authors.lastname: Tselepis
authors.forename: M E
authors.initials: ME
authors.lastname: Lekka
authors.forename: D
authors.initials: D
authors.lastname: Tsoukatos
mesh_terms: D043203:1-Alkyl-2-acetylglycerophosphocholine Esterase; D000818:Animals; D006863:Hydrogen-Ion Concentration; D007531:Isoflurophate / Q000494:pharmacology; D007700:Kinetics; D050356:Lipid Metabolism; D008861:Microsomes / Q000378:metabolism; D010741:Phospholipases A / Q000378:metabolism*; D010972:Platelet Activating Factor / Q000378:metabolism*; D013769:Tetrahymena pyriformis / Q000201:enzymology*
chemical_list: D010972:Platelet Activating Factor; D007531:Isoflurophate; D010741:Phospholipases A; D043203:1-Alkyl-2-acetylglycerophosphocholine Esterase