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Apo(a) is homologous to plasminogen: the cDNA sequence (McLean et al., Nature 1987)
Original title: cDNA sequence of human apolipoprotein(a) is homologous to plasminogen
Cloning and sequencing of human apolipoprotein(a) cDNA showed that the protein that distinguishes Lp(a) from LDL is a close relative of plasminogen: it carries a serine protease domain and two types of plasminogen-like kringle domains, one of which is present in 37 copies in the sequenced clone. This is the structural basis of two defining features of Lp(a): the kringle IV type 2 copy-number variation that sets plasma levels, and the antifibrinolytic, prothrombotic hypothesis for its pathogenicity.
Original abstract
Lipoprotein(a) is an LDL-like lipoprotein whose concentration in plasma is correlated with atherosclerosis. The characteristic protein component of lipoprotein(a) is apolipoprotein(a) which is disulphide-linked to apolipoprotein B-100. Sequencing of cloned human apolipoprotein(a) complementary DNA shows that it is very similar to human plasminogen. It contains a serine protease domain and two types of plasminogen-like kringle domains, one of which is present in 37 copies.
Summary written by lp-a.org from the published abstract; figures as published. Page updated 17 August 2026. Methods.