A study of the polypeptides of porcine serum low density lipoproteins : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Biochemistry, Massey University, New Zealand

The problem of transporting nonpolar lipids in the blood has been overcome in mammals by association of the lipid with specific proteins, to form water soluble lipoproteins. This association occurs in a reproducible fixed ratio of lipid to protein and was first demonstrated by Macheboeuf (1929). More recently the role played by the proteins in lipid transport has been the subject of intensive investigation. The circulating lipoproteins are divided into classes. Two operational systems of classification are used, one based on density and the other on electrophoretic mobility. The lipoproteins floating in a centrifugal field at a density of less than 1.006 g/cm³ are classified as VLDL. These have a flotation coefficient, S f , of between 20 and 400 and move in the pre-β band on paper electrophoresis. Those floating at density 1.006 - 1.063 g/cm³ (S f = 0 - 20) are classified as LDL and run as the β band on electrophoresis. HDL float at density 1.063 - 1.21 g/cm³ and run as the α₁ band on electrophoresis, and the chylomicrons have an S f of greater than 400 and remain at the origin in electrophoretic separations, Figure 1. [FROM INTRODUCTION