Interaction of apolipoprotein B from human serum low-density lipoprotein with egg yolk phosphatidylcholine.

A binary complex of apolipoprotein B and egg yolk lecithin has been formed which contains 250-350 mol of lipid/500000 g of protein. This particle retains many of the structural properties of native human low-density serum lipoprotein (LDL) as evidenced by the state of association of the protein, the circular dichroic spectrum, and immunological characteristics. Apolipoprotein B does not interact with lipid vesicles but rather binds a small number of phospholipid molecules in water-soluble form. This study represents the first partial reconstitution of native LDL from the delipidated apoprotein and is the initial step in a systematic investigation of the lipid binding properties of apolipoprotein B.