Reversible and irreversible interactions between elastin and plasma lipoproteins.

The interactions between radiolabeled, human plasma lipoproteins and elastin derived from bovine ligamentum nuchae were investigated using a washout technique. The interaction was characterised by Ki, a coefficient of irreversible binding, and Kr, the reversible partition coefficient. For both low-density lipoproteins (LDL) and high-density lipoproteins (HDL) the Ki values decreased as total lipoprotein concentration increased, suggesting that the binding is saturable, and were similar in magnitude to those measured by other workers using elastin derived from the human aorta. For both LDL and HDL the Kr values were independent of lipoprotein concentration in the range 0.1 microgram/ml-1.5 micrograms/ml. At a total protein concentration of 1.5 mg/ml in the incubation medium, the reversible interactions were comparable in magnitude to the irreversible.