THE PROTEIN AND LIPID COMPOSITION OF THE PLASMA OF DIFFERENT ANIMAL SPECIES DETERMINED BY ZONE ELECTROPHORESIS AND CHEMICAL ANALYSIS

1. The electrophoretic patterns and chemical composition of the plasma proteins and lipids of different animal species have been examined by zone electrophoresis on filter paper and by chemical analysis. 2. Significant differences have been found in the absolute amount and relative distribution of both the protein and lipid constituents of different animal plasmas. 3. Dog and cat plasma showed high levels of an alpha-type lipoprotein which contained most of the plasma cholesterol, whereas in human plasma cholesterol was mainly present in the large betalipoprotein fraction. 4. The herbivora in general had low levels of plasma lipoprotein and the concentration of alpha-type lipoprotein was relatively high. The horse had the highest concentrations of plasma lipids and lipoproteins of these animals. 5. The mouse constantly, and the rat and guinea-pig in some samples, showed the presence of a rapidly migrating fraction termed a pre-albumin lipoprotein. In the mouse this lipoprotein had a high proportion of lipid to protein and contained a large percentage of the plasma lipids.