Study of Salmonella endotoxin on the changes in lipid-protein interactions of membranes using Arrhenius plots of cetylcholinesterase as a tool.

Lipopolysaccharides of Salmonella typhimurium inhibit the activity of acetylcholinesterase in vitro in both synaptosomal and erythrocyte membranes. Arrhenius plots show that the transition temperatures of membrane bound acetylcholinesterase are significantly reduced in the presence of lipopolysaccharides, and the activation energies above and below transition temperature have increased with the lowering of transition temperature. These results indicate that an alteration in the fluidity of the phospholipid layer of the membranes, may be responsible for the membrane-specific effect of lipopolysaccharides on acetylcholinesterase activity.