Capillary gel electrophoresis analysis of apolipoproteins A-I and A-II in human high-density lipoproteins.

Capillary gel electrophoresis was performed on a coated capillary column filled with a replaceable low-viscosity polymer network containing sodium dodecyl sulfate (eCAP SDS-200 kit from Beckman Instruments). While apolipoprotein (apo) A-I gave an homogeneous peak in high-density lipoprotein (HDL), it appeared heterogeneous in its purified form. Apo A-II was heterogeneous in HDL as well as in purified preparations. For both proteins the relationship between peak areas and apo concentrations was linear over a large range of concentrations and, with the use of alpha-chymotrypsinogen A as an internal standard, apo A-I and apo A-II areas were measured with good precision (coefficient of variation 1.6 and 1.8%, respectively). Capillary gel electrophoresis appeared as a method of high-resolution power in the study of apo A-I and apo A-II heterogeneity and could lead to the development of an alternative method for the assay of apo HDL.