Interference by pro-apolipoprotein A-I in apolipoprotein E phenotyping using chemical precipitation procedures.
Lipoproteins of density, d less than 1.063, isolated by polyanion-cation precipitation methods, gave isoelectric focussing patterns of apolipoprotein E isoforms by rod-gel electrophoresis which differed from the corresponding patterns obtained from ultracentrifugally-derived very low density lipoproteins. The differences were sporadic and variable but the most common effect was an increased frequency of the E3 isoform. Two-dimensional analyses involving sodium dodecyl sulphate-polyacrylamide gel electrophoresis and immunoelectrophoresis against anti-apolipoprotein A-I indicated that contamination of precipitated lipoproteins with pro-apolipoprotein A-I was responsible for this phenomenon. It is suggested that two-dimensional techniques should be applied for definitive phenotyping if precipitated lipoproteins are used as source material.
Rawlings
A V
AV
Cardiothoracic Unit, Broadgreen Hospital, Liverpool, UK.
Deegan
T
T
D016632:Apolipoprotein A-I; D001054:Apolipoproteins A / Q000097:blood*; D001057:Apolipoproteins E / Q000097:blood*; D011232:Chemical Precipitation / Q000379:methods; D004591:Electrophoresis, Polyacrylamide Gel; D005189:False Positive Reactions; D006801:Humans; D006952:Hyperlipoproteinemia Type III / Q000097:blood*; D007525:Isoelectric Focusing; D007536:Isomerism; D010641:Phenotype; D011498:Protein Precursors / Q000097:blood*; D014461:Ultracentrifugation
D016632:Apolipoprotein A-I; D001054:Apolipoproteins A; D001057:Apolipoproteins E; D011498:Protein Precursors