Figure 2.

Schematic depiction of plasminogen and apoprotein (a). Apoprotein(a) is a glycoprotein with remarkable similarities to plasminogen, in both the protease part (P) and the inactive part (Pi), and in the kringle protein structure (K). The apoprotein(a) does not have KI to KIII, while it has KIV to KV; KV and subtypes 1 and 3 to 10 are expressed in single copy, while subtype 2 is pre-sent in variable copy numbers. Apoprotein(a) can vary greatly in length and molecular weight. Sialic acid (SA) with other N-glucans and O-glucans has structural functions and protects apoprotein(a) from proteases. Apoprotein(a) transports a considerable amount of oxidized phospholipids (flox), which, added to the LDL-like ones connected to apoprotein(a) via apoprotein B100 (ApoB100), make lipoprotein(a) the major carrier of oxidized phospholipids.