[Immunoelectrophoretic analysis of mink sera lipoproteins fractionated by preparative ultracentrifugation].

Using the method of preparative ultracentrifugation, four lipoprotein fractions were obtained differing in hydrate density. By means of immunoelectrophoretic analysis of the fractions, it is found that mink sera (except chilomicrons) contains at least five lipoproteins; two of them, lipoproteins 2 and 3, bind the major bulk of lipids. Lipoprotein 1 is of very low density. Lipoprotein 2 mostly belongs to the fraction with density less than 1.100 g/ml, although antigenically identical molecules with higher density were identified. Lipoprotein 3 is much more heterogeneous antigenically, electrophoretically and in its density (from 1.006 to 1.210 g/ml and higher). This protein seems to contain several structurally similar, though not identical, apoproteins. Lipoproteins 4 and 5 are very dense (more than 1.210 g/ml) and are weakly stained with Sudan black. These data, together with the results obtained in our previous studies, indicate that lipoproteins 2 and 4 are marked with genetically alloantygenic determinants.