Abstract
Rat apo E isoform patterns were determined by two-dimensional gel electrophoreisis (2-D. G. E.). Apo E in rat VLDL and HDL was separated into 3 bands by SDS gradient polyacrylamide gel and into 4 to 5 bands by IEF. On the 2-D. G. E., 4 to 5 different apo E isoforms (designated as E3, E4, etc) with isoproteins differing in MW (designated as E3a, E3b, E3c) existed as shown in Fig. 2. Rat VLDL and HDL separated by ultracentrifugation had similar apo E isoform pattern. After 4weeks of feeding with atherogenic diet, mean plasma chol and PL were increased with decrease in plasma TG. The changes in plasma lipids were accompanied with increase in chol and PL of VLDL and IDL+LDL and with decrease in VLDL-TG. Then plasma lipoproteins were isolated by 6% agarose column chromatography to exclude the loss of apo E from lipoproteins after ultracentrifugations. Distribution pattern of column-isolated lipoproteins showed decrease of VLDL peak with increasing of IDL+LDL peak in atherogenic diet group. When looked at apo E bands of isolated IDL+LDL of atherogenic diet group on SDS gel, larger particles in terms of column isolation contained high MW apo E and smaller particles contained low MW apo E proportionaly.
