ABSTRACT
The transport of lipids in the blood from one tissue to another in animals has been facilitated by the evolution of several complexes of lipids and protein which are held together by noncovalent forces and are stable in an aqueous environment. Plasma lipoproteins essentially exist as small spherical bodies with a surface layer of amphipathic phospholipids, glycolipids, cholesterol and glycoproteins. The presence of lipoproteins in the eluent from columns of sizing gels is best detected by absorption of light at 280 nm. A similar approach to detecting lipoproteins separated by density gradient ultracentrifugation is often used. Confirmation of the ratio of the different lipoproteins in a sample of human serum and in the separated fractions may be gained by gradient Polyacrylamide gel electrophoresis. The lipid-modified proteins are probably best quantified by the application of standard protein methods. This may also require confirmation of the lipid-modified version by chromatographic or electrophoretic methods.
