Interaction of dextran sulfate with low-density lipoproteins of plasma

The interaction between dextran sulfate and low-density lipoproteins of the Sf 0–10 class in phosphate buffer of pH 7.4 and ionic strength 0.1 was studied by means of analytical ultracentrifugation. The sedimentation pattern of the dextran sulfate–lipoprotein mixture at high dextran sulfate/lipoprotein weight ratios showed a boundary indicative of a soluble complex with a high sedimentation rate, and a free dextran sulfate boundary with a lower sedimentation rate. The amount of free dextran sulfate seemed to determine the distribution of various transition states of polymers, ranging from disintegrated units to large insoluble aggregates.