Biomaterial Database

A PAF-acetylhydrolase activity in Tetrahymena pyriformis cells. 1991

A D Tselepis, and M E Lekka, and D Tsoukatos

Department of Chemistry, University of Ioannina, Greece.

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.

UI	MeSH Term	Description	Entries
D007531	Isoflurophate	A di-isopropyl-fluorophosphate which is an irreversible cholinesterase inhibitor used to investigate the NERVOUS SYSTEM.	DFP,Diisopropylfluorophosphate,Fluostigmine,Bis(1-methylethyl) Phosphorofluoridate,Di-isopropylphosphorofluoridate,Diisopropylphosphofluoridate,Dyflos,Floropryl,Fluorostigmine,Di isopropylphosphorofluoridate
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008861	Microsomes	Artifactual vesicles formed from the endoplasmic reticulum when cells are disrupted. They are isolated by differential centrifugation and are composed of three structural features: rough vesicles, smooth vesicles, and ribosomes. Numerous enzyme activities are associated with the microsomal fraction. (Glick, Glossary of Biochemistry and Molecular Biology, 1990; from Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)	Microsome
D010741	Phospholipases A	Phospholipases that hydrolyze one of the acyl groups of phosphoglycerides or glycerophosphatidates.
D010972	Platelet Activating Factor	A phospholipid derivative formed by PLATELETS; BASOPHILS; NEUTROPHILS; MONOCYTES; and MACROPHAGES. It is a potent platelet aggregating agent and inducer of systemic anaphylactic symptoms, including HYPOTENSION; THROMBOCYTOPENIA; NEUTROPENIA; and BRONCHOCONSTRICTION.	AGEPC,Acetyl Glyceryl Ether Phosphorylcholine,PAF-Acether,Phosphorylcholine, Acetyl Glyceryl Ether,1-Alkyl-2-acetyl-sn-glycerophosphocholine,Platelet Aggregating Factor,Platelet Aggregation Enhancing Factor,Platelet-Activating Substance,Thrombocyte Aggregating Activity,1 Alkyl 2 acetyl sn glycerophosphocholine,Aggregating Factor, Platelet,Factor, Platelet Activating,PAF Acether,Platelet Activating Substance
D006863	Hydrogen-Ion Concentration	The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH	pH,Concentration, Hydrogen-Ion,Concentrations, Hydrogen-Ion,Hydrogen Ion Concentration,Hydrogen-Ion Concentrations
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D013769	Tetrahymena pyriformis	A species of ciliate protozoa used extensively in genetic research.	Tetrahymena pyriformi,pyriformi, Tetrahymena
D043203	1-Alkyl-2-acetylglycerophosphocholine Esterase	A lipoprotein-associated PHOSPHOLIPASE A2 which modulates the action of PLATELET ACTIVATING FACTOR by hydrolyzing the SN-2 ester bond to yield the biologically inactive lyso-platelet-activating factor. It has specificity for phospholipid substrates with short-chain residues at the SN-2 position, but inactive against long-chain phospholipids. Deficiency in this enzyme is associated with many diseases including ASTHMA, and HYPERCHOLESTEROLEMIA.	PAF Acetylhydrolase,Platelet-Activating Factor Hydrolase,Lipoprotein-Associated Phospholipase A(2),Lipoprotein-Associated Phospholipase A2,Lp-PLA(2),Lp-PLA2,PAF 2-Acetylhydrolase,PAF 2-Acylhydrolase,PAF Acetylhydrolase II,Platelet-activating Factor Acetylhydrolase IB,1 Alkyl 2 acetylglycerophosphocholine Esterase,2-Acetylhydrolase, PAF,Acetylhydrolase II, PAF,Acetylhydrolase, PAF,Esterase, 1-Alkyl-2-acetylglycerophosphocholine,Factor Hydrolase, Platelet-Activating,Hydrolase, Platelet-Activating Factor,Lipoprotein Associated Phospholipase A2,Lp PLA2,PAF 2 Acetylhydrolase,PAF 2 Acylhydrolase,Phospholipase A2, Lipoprotein-Associated,Platelet Activating Factor Hydrolase,Platelet activating Factor Acetylhydrolase IB
D050356	Lipid Metabolism	Physiological processes in biosynthesis (anabolism) and degradation (catabolism) of LIPIDS.	Metabolism, Lipid