Displacement of palmitate from albumin by chlorophenoxyisobutyrate.

The effect of chlorophenoxyisobutyrate, a hypolipidemic drug that decreases plasma free fatty acids, triglycerides, and cholesterol, on the partitioning of ¹⁴C]-palmitate between hexane and bovine serum albumin was studied at 37°. In this system, hexane served as a hydrophobic trap for free fatty acids displaced from BSA by chlorophenoxyisobutyrate, allowing less than 0.3% to remain in the aqueous phase. As the concentration of chlorophenoxy isobutyrate was raised from 0.4 to 3.2 mM, there was a progressive displacement of palmitate from the ¹⁴C]-palmitate-BSA complex into hexane, the magnitude being dependent on the initial $\text{V}$ value (moles palmitate bound/mole BSA). Beginning with ¹⁴C]-palmitate in hexane, chlorophenoxyisobutyrate (2 mM) decreased the moles palmitate bound/mole of BSA by 16% at $\text{V}$ = 0.2, and 34% at $\text{V}$ = 3.0.