FIGURE 7.

A schematic model for the activation of PLA₂ in the course of action on DPPC: (i) monomeric PLA₂ in solution, (ii) binding of monomeric PLA₂ to the substrate interface, (iii) slow dimerization of PLA₂ during the lag phase, (iv) formation of “molten dimers” before the burst, (v) formation of protofibrillar oligomers of PLA₂ with high catalytic activity, and (vi) emergence of amyloid-like fibrils. The levels of activity and fluorescence reporter parameters are indicated for each stage. See text for details.