ABSTRACT
This chapter reviews the literature which describes the behavior of phospholipase A2 in mammalian cell membranes subjected to oxidative damage. The bilayer arrangement of membrane phospholipids represents only one of many possible phospholipid organizational states. Structural transitions not only result from the mixing of different phospholipids, but are observed under certain conditions for pure phospholipid preparations such as phosphatidylcholine. The transition from bilayer to hexagonal packing has been described for mixed-chain phosphatidylcholines in membranes in the region of the lipids thermotropic phase transition. The presentation of selected evidence indicating a role for phospholipase A2 in membrane lipid peroxidation and the accompanying speculations were intended to call attention to one among several dynamic events involving free radical damage and turnover of cell constituents. Lipid peroxidation may indeed be a “normal” cellular event, but the enzymatic elimination of lipid peroxides quickly erases all but the most distal vestiges of the process.
