Solubilization and purification of an acetyl-LDL binding membrane protein from human leukocytes

An acetyl-LDL receptor in the human leukocyte membrane might have some importance in the generation of foam cells in the atherosclerotic lesion. We show purification of a human leukocyte membrane protein which exhibits ac-LDL-specific binding. Our attempts to solubilize this protein from the leukocyte's membrane fraction involved the usage of the non-ionic detergents Triton X-114 and beta-D-Octylglucoside. Our scheme for the purification of the acetyl-LDL binding protein included ion exchange chromatography and affinity chromatography. Following solubilization the ac-LDL binding activity was assayed by ligand blotting, demonstrating polyvinylsulfate sensitive binding of ac-LDL to a single, acidic 280 000 D membrane protein in the crude membrane fraction.