[Isoelectric focusing and immunoblotting identification of human ApoE phenotype]

A simple, rapid and accurate method for phenotyping sera apoE has been developed. In this method 10 microliters serum or plasma are incubated with Dithiothreitol and Tween-20 for 15 min and then applied to 5% polyacrylamid gel containing pH 4-8 ampholyte and 3 mol/L urea. After 2 h focusing, the apoE bands are transferred to Nitrocellulose membrane. apoE bands are made visible by immunoblotting and TMB is used as the substrate. Identification phenotype is easily accomplished by noting the location and number of protein bands. 56 samples shows apoE 3/3 in 47 cases, apoE 2/3 in 2 cases, and apoE 3/4 in 7 cases. This method is well suited for large-scale population studies and clinical labs.