Separation of the isoprotein forms of apoprotein A-I of rat, rabbit and human HDL by combined isoelectrofocusing and SDS-polyacrylamide gel electrophoresis.
The distribution and the relative content of the isoprotein forms (isoforms) of apoprotein A-I (apo A-I) of HDL isolated from rat, rabbit and human plasma were studied by combined isoelectrofocusing and SDS-polyacrylamide gel electrophoresis. Rat apo A-I consists of seven isoforms having the same molecular weight (27,000) and moving in the 6.44-5.58 pH range. Isoforms 4, 5 and 6 are the major ones. Both rat HDL2 (1.090-1.210 g/ml) and purified rat apo A-I contain additional minor bands (designated 4a, 5a and 6a) which have the same isoelectric point as isoforms 4-6 but higher molecular weight (27,900). It is suggested that they might represent precursors of the main apo A-I isoforms. Rabbit apo A-I contains five isoforms focusing in the 5.69-5.34 pH range. Isoform 4 accounts for about 90% of apo A-I mass. Human apo A-I consists of five isoforms focusing in the pH range 5.91-5.0. Isoforms 3 and 4 are the main ones: their respective contents show high degrees of individual variation.
D000818:Animals; D016632:Apolipoprotein A-I; D001053:Apolipoproteins / Q000097:blood / Q000302:isolation & purification*; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D007525:Isoelectric Focusing; D007536:Isomerism; D008075:Lipoproteins, HDL / Q000302:isolation & purification*; D008297:Male; D011817:Rabbits; D051381:Rats; D011919:Rats, Inbred Strains
D016632:Apolipoprotein A-I; D001053:Apolipoproteins; D008075:Lipoproteins, HDL