Studies of Oleate Binding to Rat Liver Plasma Membranes

The binding of [14C]oleate to rat liver plasma membranes was examined under various conditions in vitro. In protein free incubation mixtures binding was saturable, inhibited by excess cold oleate, virtually abolished by heat denaturation of the membranes, reversible by post-incubation with cold oleate or albumin, and pH and temperature dependent. When [14C]oleate was incubated in the presence of albumin or beta-lactoglobulin, the amount of membrane bound oleate was a function of the calculated free oleate concentration in the incubation mixture. Trypsin significantly inhibited binding. Further analysis suggests that membranes contain 10(15) high affinity (Kav = 2 x 10(8)M-1) oleate binding sites/mg protein.