Contamination of commercial phosphatidylcholine by phospholipase A.
During the course of a study involving the assay of a membrane-bound phospholipase A2 it was observed that a commercial preparation of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine used as substrate had intrinsic lipolytic activity at pH 8.5. Further investigation revealed a Ca2+-dependent phospholipase A largely susceptible to treatment by the alkylating reagent p-bromophenacyl bromide or by heat (15 min at 120 degrees C). Complete separation of enzyme and phospholipid could be achieved by thin-layer chromatography. Such a contamination was not observed in a chemically identical phosphatidylcholine obtained from a different supplier. These observations may be relevant to investigators using commercial preparations of phospholipids in a variety of studies, including intracellular phospholipase A2 determination.
Department of Obstetrics and Gynaecology, University of Western Ontario, London, Canada.
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Filgueiras
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Possmayer
D000098:Acetophenones; D002855:Chromatography, Thin Layer; D004340:Drug Contamination; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D010713:Phosphatidylcholines / Q000032:analysis*; D010741:Phospholipases A; D054467:Phospholipases A2
D000098:Acetophenones; D010713:Phosphatidylcholines; D010741:Phospholipases A; D054467:Phospholipases A2; C006821:4-bromophenacyl bromide