Serum low density lipoprotein separation: a simple procedure

Reference methods for serum low density lipoprotein (LDL) separation are time-consuming and the salts used in density-gradient ultracentrifugation may cause chemical and/or immunological changes in the lipoprotein structure. A method has been developed to provide native LDL suitable for chemical and immunochemical studies. The three step procedure involves firstly the separation of very low density lipoproteins by non-density adjusted ultracentrifugation, secondly the separation of low from high density lipoproteins by LDL precipitation with PEG-6000, and finally the re-dissolution of the pellet in NaCl 150 mmol/l. The effectiveness of LDL separation, as well as the preservation of the electrophoretic mobility of the LDL molecules, was verified by electrophoresis in agarose gel, and the maintenance of the immunochemical reactivity of apolipoprotein B was verified by an immunochemical assay.