Fig. 3. Structure of Lp(a). (A) Lp(a) consists of a LDL-like moiety covalently linked by a single disulfide bond to the glycoprotein apo(a). The LDL-like moiety contains a single molecule of apoB100, an outer shell of PLs and unesterified FC, and a neutral lipid core consisting of CEs (primarily) and TGs. OxPLs are predominantly covalently bonded to apo(a), but are also found covalently linked to apoB100 and free in the lipid moiety. (B) Apo(a) consists of 10 different domains homologous to plasminogen K4 (named KIV in apo[a]), a KV, and an inactive, protease-like domain.

Lp(a), lipoprotein(a); LDL, low-density lipoprotein; apo(a), apolipoprotein(a); apoB100, apolipoprotein B100; PL, phospholipid; FC, free cholesterol; CE, cholesteryl ester; TG, triglyceride; OxPL, oxidized phospholipid; K4, kringle 4; KV, kringle 5-like domain; T, tail domain.