PLA2 activity in tetrahymena pyriformis. Effects of inhibitors and stimulators

Péter Kovács, György Csaba

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36 Citations (Scopus)


Phospholipase A2 (PLA2) is an enzyme which participates in signalling mechanisms cleaving arachidonate from sn-2 position of glycerophospholipids. In this study we have verified the existence of a PLA2-like activity in the free living protozoan, Tetrahymena pyriformis GL. This activity is Ca2+-independent, EDTA (10 mM) has no effect on its activity. Quinacrine (0.1 mM) and 4-bromophenacyl bromide (BPB; 0.1 mM) inhibited, melittin (20 μg/ml) significantly stimulated the PLA2 activity and the release of free arachidonic acid (AA) from 1-acyl 2-14C-arachidonyl-3-phosphatidylethanolamine substrate. Melittin stimulated PLA2 hyperactivity is Ca2+-dependent. There was no considerable alteration in the PLA2 activity by stimulation of the activity by tyrosine kinase (with vanadate, H202), phospholipase C (PLC) (with phorbol 12, 13-dibutyrate) or G-proteins (with NaF, A1F4), thus in Tetrahymena PLA2 activity seems to be independent of these - in Tetrahymena (also functioning)-signalling pathways. Treatment with quinacrine and BPB leads to decreased synthesis and disturbed breakdown of phospholipids and phosphoinositides. These findings suggest that PLA2 activity is in connection with the phospholipid metabolism of Tetrahymena.

Original languageEnglish
Pages (from-to)233-247
Number of pages15
JournalJournal of Lipid Mediators and Cell Signalling
Issue number3
Publication statusPublished - Mar 1 1997


  • Phospholipase
  • Phospholipids
  • Tetrahymena

ASJC Scopus subject areas

  • Immunology
  • Pharmacology

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