Lipid transport in the avian species. Part 2. Isolation and characterization of lipoprotein A and lipoprotein B, two major lipoprotein families of the male turkey serum lipoprotein system.

(1) Male turkey serum contains two major lipoprotein families designated as LP-A and LP-B in its lipoprotein density classes. These two lipoprotein families were separated from each of the lipoprotein density classes by affinity chromatography on concanavalin A-Sepharose 4B. LP-A was present in the unretained and LP-B in the retained fractions. Both lipoprotein families were characterized by determination of their immunological and electrophoretic properties, the flotation coefficient and chemical composition. (2) LPb was distributed over a wider density range than LP-A. Seventy-four percent of LP-B was found in the LDL, 17% IN The VLDL and 8% in the HDL. In contrast, 98% of LP-A was present in the HDL and 2% in the LDL fractions: there were only trace amounts of LP-A in the VLDL. (3)Immunological and electrophoretic studies showed that the protein moiety of LP-A contained only the two non-identical A-I and A-II polypeptides of ApoA. The protein moiety of LP-B consisted only of ApoB. (4) Isolation of LP-A and LP-B from the major lipoprotein density classes provided further experimental evidence to confirm the existence of chemically distinct lipoprotein families as the fundamental physical-chemical entities of the serum lipoprotein system.