Lipoprotein electrophoretic analysis

When the sulphate groups are removed using the procedures described by Araki (A2), the adsorption effects as well as the electro-osmotic flow are considerably reduced. As a consequence, P-lipoproteins move at nearly the same rate as in paper-electrophoresis experiments. Moreover, sulphate-free agar is very suitable to electrophoretic analysis of mucopolysaccharides, as the background of electrophoresis diagrams stained by metachromatic techniques is practically colorless (R.E.P.A. Ballieux, personal communication). As stained electrophoresis diagrams... 

Table 20-3 lists the principal plasma proteins and their half-lives, pi, molecular weights, and preferred method of analysis the individual proteins are listed in the order of their electrophoretic mobilities in agarose gels at pH 8.6. These proteins are described later in this chapter other chapters in this book describe many more proteins enzymes (see Chapter 21) lipoproteins (see Chapter 26) hormones (see Chapter 28) and hemoglobin, fibrinogen, and other coagulation proteins (see Chapter 31). The interim consensus reference intervals for 14 plasma proteins are listed in Table 20-4, pending the publication of more definitive intervals. . 

Electrophoretically, sera of diabetic patients have been found to have a pre-P lipid band (Vemet and Smith, 1961 Pantelakis et al., 1964). Comparative analysis with ultracentrifugal data has indicated that this pre-ji-lipoprotein has the flotation rate of VLDL with St 15-100 (Pantelakis et al, 1964). 

Lipids circulate in blood as constituents of the lipoproteins or bound to albumin (free fatty acids). Electrophoretic separation of plasma proteins on paper is a relatively easy and convenient method for the semi-quantitative analysis of lipoproteins. Staining the strips with dyes which only respond to lipids reveals three well-defined bands when normal plasma or serum is analyzed. The a-lipoprotein migrates the farthest from the origin. The pre-j8, previously called the a-2-hpoprotein, and the jS-Hpoprotein, are closer to the origin. In the post-prandial normal serum, and in some hyperlipemic sera, after fasting, a fourth band can be seen at the origin. This band is due to neutral fat particles with a small protein content (i.e. chylomicron fraction). 

Multi-variable or cold-ethanol precipitation techniques yielded plasma protein fractions rich in lipoprotein (Oncley et al. 1949). These isolation procedures were extremely important. They demonstrated that physical properties such as solubility could be studied with lipoproteins as well as other proteins. Electrophoretic mobilities and specific refractive increments of lipoproteins were shown to be measurable properties (Armstrong et al. 1947 a and 1947 b). A detailed analysis of lipoprotein composition was undertaken (Oncley et al. 1950). 

Analytical methods employing paper electrophoresis (for bibliography see Pezold 1961) have been used in lipoprotein research since the introduction of Sudan Black B as a Upid stain (Swahn 1952). Paper electrophoresis is a deceptively simple technique. The analysis of electrophoretic data is more complex. While a number of important studies have been published, it has sometimes been difficult to interpret data showing arbitrary ratios between partially separated and poorly characterized serum lipoproteins whose concentrations were estimated by non-specific staining. 

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