Abstract
Atomic Force Microscopy (AFM) has been used to investigate the in situ phospholipase A2 (PLA2) degradation of one-component and two-component phospholipid mica supported bilayers composed of dipalmitoylphosphocholine (DPPC) and dimyristoylphosphocholine-distearoylphosphocholine (DMPC-DSPC). The solid supported phospholipid bilayers were imaged in contact mode AFM. Hydrolysis of the lipid bilayers was initiated by injection of PLA2 into the fluid cell of the atomic force microscope and the enzymatic degradation was monitored in situ at room temperature. The AFM pictures show that the PLA2 hydrolysis displays an increased activity towards certain preexisting interfacial regions in the one-component DPPC bilayer due to preformed holes appearing in the solid supported lipid film. It is found that the PLA2 hydrolysis activity, determined by the amount of lipid bilayer disappearing from the mica substrate, varies almost linearly as a function of time elapsed after addition of PLA2. For the equimolar DMPC-DSPC lipid bilayer mixture, an increased PLA2 activity is observed towards DMPC enriched small-scale lipid structures.
| Original language | English |
|---|---|
| Journal | Probe Microscopy |
| Volume | 2 |
| Issue number | 2 |
| Pages (from-to) | 169-175 |
| Number of pages | 7 |
| ISSN | 1355-185X |
| Publication status | Published - 1 Dec 2001 |
Keywords
- Atomic force microscopy
- Interfaces
- Langmuir Blodgett film
- Lipid bilayer
- Lipid domains
- Phospholipase A
- Phospholipids