The hydrolysis reaction of phospholipid bilayer catalyzed by a phospholipase A2 (PLA2) enzyme has been investigated by atomic force microscope (AFM) and sum frequency generation (SFG) observations at a molecular level.  Based on the high catalytic selectivity of PLA2 toward L  -enantiomer, different kinds of supported bilayers made of L  - and D  -dipalmitoylphophatidylcholine (DPPC) were prepared on mica surface by the Langmuir-Blodgett (LB) technique. AFM observations for L  /L  bilayer show that the hydrolysis rate for L  -DPPC is significantly increased by PLA2 and most of the hydrolysis products are likely to leave substrate surface in 40 min. As D -entiomers are included in the bilayer, the hydrolysis rate is largely decreased. The hydrolysis preferentially occurs on the perimeters of structural defects in the bilayer surface while the bilayer structures are preserved during the hydrolysis process. Based on these observations, a novel kinetics model is proposed to quantitatively account for the hydrolysis of the phospholipid bilayers.

In situ AFM and SFG studies on the hydrolysis reaction of lipid bilayer catalyzed by phospholipase A<sub>2</sub>

244th National Meeting (2012)

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In situ AFM and SFG studies on the hydrolysis reaction of lipid bilayer catalyzed by phospholipase A2

In situ AFM and SFG studies on the hydrolysis reaction of lipid bilayer catalyzed by phospholipase A₂