Apolipoprotein E2-Christchurch (136 Arg----Ser). New variant of human apolipoprotein E in a patient with type III hyperlipoproteinemia.
The primary structure of apolipoprotein E (apo E) was investigated in seven type III hyperlipoproteinemic patients with the apo E-2/2 phenotype. Six of the patients had identical two-dimensional tryptic peptide maps. These differed from the normal apo E3 map by the altered mobility of a single peptide. Amino acid analysis and sequencing showed that apo E2 in these patients had a substitution of 158 Arg----Cys. The presence of this mutation in six of the seven type III patients confirms that this is the most common form of apo E2. The seventh type III patient had a unique map with a new peptide resulting from a substitution of 136 Arg----Ser. He was heterozygous for this and for the more common apo E2 (158 Arg----Cys) variant. His very low-density lipoprotein contained approximately five times more apo E2 (136 Arg----Ser) than apo E2 (158 Arg----Cys), as determined by cysteamine treatment and peptide mapping. This new apo E2 mutant thus appears to contribute significantly to the patient's hyperlipidemia.
D000328:Adult; D000595:Amino Acid Sequence; D001057:Apolipoproteins E / Q000235:genetics*; D005260:Female; D006801:Humans; D006952:Hyperlipoproteinemia Type III / Q000235:genetics*; D026503:Low Density Lipoprotein Receptor-Related Protein-1; D008297:Male; D008875:Middle Aged; D009154:Mutation; D010375:Pedigree; D010449:Peptide Mapping; D011956:Receptors, Cell Surface / Q000378:metabolism
D001057:Apolipoproteins E; D026503:Low Density Lipoprotein Receptor-Related Protein-1; D011956:Receptors, Cell Surface