Journal of Lipid Research, Vol 28, 1495-1507, Copyright © 1987 by Lipid Research, Inc.
Gradient gel electrophoresis-immunoblot analysis (GGEI): a sensitive method for apolipoprotein profile determinations
M Lefevre, JC Goudey-Lefevre and PS Roheim
Department of Physiology, Louisiana State University Medical Center, New Orleans 70112-2822.
A method is described which will determine the distribution of individual
apolipoproteins within the HDL subclasses. This method requires 1-2
microliters of plasma per determination and involves six steps: 1)
electrophoresis of samples on non-denaturing 2-30% concave acrylamide
gradient gels; 2) electrophoretic transfer of the lipoproteins to
charge-modified nylon membranes; 3) fixation of the transferred
lipoproteins with glutaraldehyde; 4) immunolocalization of the
apolipoproteins with iodinated monospecific antibodies; 5) autoradiography
followed by densitometry; and 6) reduction of the data to provide a plot of
percent distribution versus particle size. When this method was applied to
the analysis of rat apolipoproteins, differences were noted in the
distribution of apoA-I, apoA-IV, and apoE. The majority of apoA-I was
localized to HDL particles between 9 and 12 nm in diameter, with a median
diameter of 10.0 nm, while apoE resided on substantially larger particles
with a median diameter of 12.5 nm. ApoA-IV could be localized to three
distinct areas: an HDL particle with a median diameter approximately 0.4 nm
larger than apoA-I HDL, a particle smaller than albumin (lipoprotein-free
apoA-IV), and a particle of 7.6 nm that does not appear to contain apoA-I
or apoE.