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Analysis of human apolipoproteins C by isoelectric focusing in immobilized pH gradients
Author(s) -
Haase Regina,
MenkeMöllers Irene,
Oette Kurt
Publication year - 1988
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.1150090917
Subject(s) - chemistry , isoelectric focusing , chromatography , apolipoprotein b , immobilized ph gradient , very low density lipoprotein , isoelectric point , lipoprotein , biochemistry , cholesterol , enzyme
Apolipoproteins C are involved in many ways in the metabolism of plasma lipoproteins. Apolipoproteins C from the delipidated VLDL of 35 controls and 165 normo‐and hyperlipoproteinemic patients were analyzed by isoelectric focusing on an immobilized pH gradient, pH 4.0–5.0, with 7 M urea, which raised the apparent pH range to 4.8–5.7. This method is an improvement over conventional isoelectric focusing with carrier ampholytes with regard to both resolution and reproducibility. Due to the high resolution (0.1 pH units per cm) additional apolipoprotein C‐III bands: C‐III 0 A 1 , C‐III 0 A 2 , C‐III 1 C and C‐III 2 C (the designations A, anodic, and C, cathodic, refer to direction of migration on IEF in relation to the main band) are described for the first time. The possible artifactual nature of these protein bands could be excluded. Cleavage with neuraminidase and peptidases, immunological detection and/or two‐dimensional electrophoresis were used to obtain more information. The additional bands seem, in part, to be hydrolysis products of carboxypeptidase A (C‐III 1 C, C‐III 2 C). The appearance of C‐III 1 C and C‐III 2 C was dependent upon the serum triglyceride concentration. The percent distribution of C apolipoproteins in very low density lipoproteins (VLDL) from control serum agreed with previously published data. Apolipoproteins C can also be focused in immobilized pH gradients from VLDL and serum without delipidation.