Fractionation and characterization of the low-density lipoproteins of hen's egg yolk

The LDF of hen's egg yolk prepared by a modified method was found to be soluble in water. In this low-density solvent it was possible to separate LDF by flotation into fractions (LDF₁ and LDF₂) owing in part to the maximum effect of the difference in their partial specific volumes. About one-fifth of LDF was estimated to consist of LDF₁, the remainder being LDF₂. Both fractions were polydisperse with molecular weights ranging from 0.5 · 10⁶ to 34 · 10⁶ (mol. wt. 10.3 · 10⁶) for LDF₁ and 0.5 · 10⁶ to 14 · 10⁶ (mol. wt. 3.3 · 10⁶) for LDF₂. Since LDF₁ contained 86.8% and LDF₂ 83.2% lipid, the mean size of their protein moieties was about 1.4 · 10⁶, respectively.