Isoelectric focusing of human serum high density lipoprotein in the presence of radioactive ampholines.

Preparative isoelectric focusing of a serum high density lipoprotein fraction (rho 1.063-1.125 g/ml) in the presence of radioactive Ampholines showed that there were no significant 14-C-activity peaks in the lipoprotein region of the pH gradient. This suggests that the discrete lipoprotein subspecies obtained by electrofocusing are not artefacts caused by the binding of Ampholines to serum high density lipoprotein.