Melittin binds to secretory phospholipase A2 and inhibits its enzymatic activity

Shamsher S. Saini, Johnny W. Peterson, Ashok K. Chopra

Research output: Contribution to journalArticle

53 Scopus citations

Abstract

Synthetic melittin inhibited the enzymatic activity of secretory phospholipase A2 (PLA2) from various sources, including bee and snake venoms, bovine pancreas, and synovial fluid from rheumatoid arthritis patients, irrespective of substrate (e,g., [14C]-phosphatidylcholine or phosphatidylethanolamine vesicles and [3H]-oleic acid-labeled E.coli). A Lineweaver-Burk analysis showed that melittin was a noncompetitive inhibitor of bee venom PLA2, causing a change in V(max) from 200 to 50 units/min/mg of protein. The K(m) remained unchanged (0.75 nmole). Melittin inhibited approximately 50% of purified bee venom PLA2 activity in a 30:1 molar ratio (melittin:enzyme). Because the enzyme kinetics indicated a PLA2-melittin interaction, a melittin-sepharose affinity column was used to purify a PLA2 from human serum. Further, an enzyme-linked assay was developed to quantitate PLA2 activity in biological fluids using avidin-peroxidase and ELISA plates coated with biotinylated melittin. These observations may have potential therapeutic significance, as well as provide a convenient basis for the isolation and quantitation of PLA2.

Original languageEnglish (US)
Pages (from-to)436-442
Number of pages7
JournalBiochemical and Biophysical Research Communications
Volume238
Issue number2
DOIs
StatePublished - Sep 18 1997

Keywords

  • Bee venom
  • Bovine pancreas
  • Enzyme kinetics
  • Fatty acid
  • Inflammation
  • Melittin
  • Phospholipase A
  • Phospholipid
  • Rheumatoid arthritis
  • Snake venom
  • Synovial fluid

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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