Abstract

Monophosphoinositide chromatographically purified from bovine brain extract shows in in vitro experiments a high capacity to bind noradrenaline. Using a simplified two-phase model consisting of an aqueous phase with noradrenaline and a lipophilic organic phase with monophosphoinositide, thermodynamic variables are calculated for the binding reaction. The binding capacity and the partition of lipid was strongly influenced by the presence of bivalent cations. From the results obtained a possible receptor function of monophosphoinositide for noradrenaline in synaptosomes is discussed.