Me. Gadd et Rl. Biltonen, Characterization of the interaction of phospholipase A(2) with phosphatidylcholine-phosphatidylglycerol mixed lipids, BIOCHEM, 39(32), 2000, pp. 9623-9631
The first requirement in the hydrolysis of phospholipid bilayers by phospho
lipase A(2) is the interaction of the enzyme with the bilayer surface. The
catalytic ability of phospholipase A(2) has been shown to be extremely sens
itive to the topology of the bilayer to which it binds and hydrolyzes. Phos
pholipid bilayer properties and composition such as unsaturation, charge, a
nd the presence of reaction products are known regulators of the catalytic
activity of phospholipase A(2) toward the phospholipids and influences the
binding of enzyme to the membrane. We show in this paper that the effect of
increased anionic lipid results in enhanced binding that can be described
quantitatively in terms of a simple phenomenological model. However, the in
teraction with anionic lipid does not singularly dominate the thermodynamic
s of binding, nor can the lag phase observed in the time course of hydrolys
is of large unilamellar vesicles simply be the result of limited interactio
n between the enzyme and the bilayer. Furthermore, we show that phospholipa
se A(2) from Akgistrodon piscivorus piscivorus can exist in at least two bi
layer-bound states and that the absence of a fluorescence change upon mixin
g the enzyme with lipid bilayers does not necessarily indicate the absence
of an interaction.