Studies on an additional pre-beta-lipoprotein, sinking pre-beta (SPB). I. Isolation and characterization.

The occurrence on cellulose acetate and agarose gel electrophoresis of additional bands with the mobility of pre-beta-lipoprotein (LP) has recently been linked to ischemic heart disease (IHD). In the present study, one of these additional pre-beta-LP fractions, earlier designated as 'pre-beta-LP' and now defined on agarose gel electrophoresis, was isolated by preparative ultracentrifugation and gel filtration. The characterization of this pre-beta-1-LP revealed a 'sinking pre-beta-LP' (SPB) of density 1.050-1.080 g/ml. SPB shared its major antigenic determinant with low-density lipoproteins (LDL) and resembled closely LDL with regard to its lipid composition. Specific anti-LP(a) serum confirmed the presence of LP(a) antigen in the purified SPB preparation.