Polymorphism and Distribution of Apo(a).

Several apo(a) isoforms, controlled by a series of alleles Lp(a)F, Lp(a)B, Lp(a)S1, Lp(a)S2, Lp(a)S3, Lp(a)S4 and null, were found in 470 healthy Japanese by 4% SDS-PAGE and immunoblotting techniques. There was a strong inverse relationship between the apparent molecular weight of apo(a) isoforms and plasma concentrations of Lp(a). Lp(a) in d < 1.006 fraction increased 2-4h after oral fat load. Lp(a) exhibited a marked avidity for triglyceride-rich lipoprotein (TRL), and we suggest that the TRL-bound Lp(a) is the intact Lp(a) derived from serum. We demonstrated that the lipid-free apo(a) does not contain apo B-100 in serum, and has a molecular mass of ca 200 kDa. The free apo(a) level in normal subjects was 1.75 mg/dl (as Lp(a)) and was no different from the level in CAD patients.