Phospholipase A(2) hydrolysis of supported phospholipid bilayers: A neutron reflectivity and ellipsornetry study

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We have investigated the phospholipase A(2) catalyzed hydrolysis of supported phospholipid bilayers using neutron reflection and ellipsometry. At the hydrophilic silica-water interface, hydrolysis of phosphatidy1choline bilayers by phospholipase A(2) from Naja mossambica mossambica venom is accompanied by destruction of the bilayer at an initial rate, which is comparable for DOPC and DPPC but is doubled for POPC. The extent of bilayer destruction at 25 degreesC decreases from DOPC to POPC and is dramatically reduced for DPPC. Neutron reflectivity measurements indicate that the enzyme penetrates into the bilayers in increasing order for DOPC, POPC, and DPPC, while the amount of enzyme adsorbed at the interface is smallest for DPPC and exhibits a maximum for POPC. Penetration into the hydrophobic chain region in the bilayer is further supported by the fact that the enzyme adsorbs strongly and irreversibly to a hydrophobic monolayer of octadecyltrichlorosilane. These results are rationalized in terms of the properties of the reaction products and the effect of their accumulation in the membrane on the kinetics of enzyme catalysis.


  • H P Vacklin
  • Fredrik Tiberg
  • G Fragneto
  • R K Thomas
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Biochemistry and Molecular Biology
Original languageEnglish
Pages (from-to)2811-2821
Issue number8
Publication statusPublished - 2005
Publication categoryResearch