Characterization of an apolipoprotein C-III mutant by high-performance liquid chromatography and time-of-flight secondary ion mass spectrometry.
Apolipoprotein (apo) C-III isoforms from a patient with a mutant apo C-III and from controls were isolated to homogeneity by isoelectric focusing and subjected to proteolytic digestion. The peptides obtained were separated by reversed-phase high-performance liquid chromatography, and their molecular masses were determined by time-of-flight secondary ion mass spectrometry. Molecular masses of peptides derived from apo C-III0, C-III1 and C-III2 were indistinguishable from control preparations, whereas the mutant apo C-III contained a COOH-terminal, carbohydrate-containing peptide with an abnormal retention time in high-performance liquid chromatography and a molecular mass higher by 291 daltons owing to oversialation at position 74 of the amino acid sequence (apo C-III3).
D000595:Amino Acid Sequence; D053305:Apolipoprotein C-III; D001056:Apolipoproteins C / Q000032:analysis* / Q000235:genetics; D002851:Chromatography, High Pressure Liquid; D005260:Female; D006801:Humans; D006868:Hydrolysis; D007525:Isoelectric Focusing; D013058:Mass Spectrometry / Q000379:methods; D008875:Middle Aged; D008970:Molecular Weight; D009154:Mutation; D010446:Peptide Fragments / Q000032:analysis
D053305:Apolipoprotein C-III; D001056:Apolipoproteins C; D010446:Peptide Fragments