Human very low density lipoproteins: loss of electrophoretic mobility on enzymatic removal of sialic acid residues.

Incubation of very low density lipoproteins (VLDL) from three hyperlipoproteinemic patients with neuraminidase resulted in a progressive liberation of sialic acid residues. After the original sialic content had been reduced by approx. 75% a lipoprotein fraction having zero electrophoretic mobility on paper appeared. This fraction increased until, after the removal of all the sialic acid residues, the mobility of the entire VLDL fraction was reduced to zero.