APOLIPOPROTEIN AI, AII, AND AIV ISOFORMS IN PLASMA DETERMINED BY AUTOMATED ISOELECTRIC-FOCUSING WITH PHASTSYSTEM(TM) AND IMMUNOFIXATION

Distinct genetic variants of apolipoprotein (ape) AI have been shown t o influence concentrations of high-density lipoprotein (HDL) cholester ol. The genetic polymorphism of apo AIV may modulate HDL-cholesterol, plasma triglycerides, and lipoprotein(a) concentrations. There is evid ence for an antagonizing role of apo AII in reverse cholesterol transp ort. Since genetic polymorphisms and variants of these apolipoproteins are detectable by isoelectric focusing (IEF), we developed a rapid an d easy automated method for IEF analysis of apos AI, AII, and AIV on s elf-made or commercially available gels, using the PhastSystem(TM). Di luted plasma or serum samples (1 mu L) are applied automatically onto the gel and IEF is carried out for 35-45 min. Afterwards, the apo A ba nds are precipitated by specific polyclonal antibodies and visualized by automated silver staining. This rapid procedure is suitable as a ro utine or screening method for IEF analysis of these major HDL apolipop roteins.