Separation of two serum very low density lipoprotein fractions using starch block electrophoresis

Abstract

A quantitative electrophoretic method has been developed in order to differentiate very low density (VLDL) pre-β lipoproteins from late pre-β lipoproteins using starch as a supporting medium. It was possible to obtain a bimodal distribution of lipoprotein lipids from VLDL which on agarose gel electrophoresis had a pre-β band and a late pre-β band. Optimal conditions were: ammonium carbonate buffer, μ = 0.025, dialysis prior to electrophoresis. Agarose gel electrophoresis demonstrated that the fast and slow components obtained on starch block electrophoresis corresponded to the pre-β and late pre-β band respectively. With increasing migration towards the anode the ratio of cholesterol to triglycerides decreased continuously. It is suggested that the fast triglyceride rich component represent newly secreted VLDL species and the slower component mainly post-lipolytic particles. The pre-β band on agarose gel electrophoresis might represent more newly secreted VLDL than the late pre-β band. However, it cannot be excluded that part of late pre-β lipoproteins may be secreted de novo.

Key Words:

• ionic strength
• late pre-β lipoprotein
• pre-β lipoprotein
• preparative electrophoresis
• starch
• very low density lipoproteins