Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.7 (plasmin)
 9,023 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Lipoprotein(a) is a genetically regulated trait, and its concentration in serum seems to be independent from that of other lipoprotein classes. It can be detected by ultracentrifugation in the d = 1.05-1.12 g/ml density range. Based on epidemiological observations Lp(a) is an independent risk factor for coronary heart disease. Its structure resembles LDL, but contains, in addition to apolipoprotein B 100, the disulphide-linked apoprotein(a). Apoprotein(a) shares a striking homology with plasminogen, consisting multiple repeating domains similar to kringle IV, a single kringle V and an inactive protease segment. The heterogeneity of Lp(a) complex is determined by the apoprotein(a) moiety. It seems so, that atherogenic properties of Lp(a) can be explained by its binding to glycosaminoglycans and inhibition of fibrinolysis. This latter effect is carried out by the kringle domains, which can interact with the plasminogen activators and plasmin binding sites on endothelial surface. The atherogenic properties of Lp(a) are expressed over 30 mg/dL serum concentration. Well-known antilipidemic drugs do not affect its serum level and genetically determined phenotype. Diseases leading to secondary hyperlipoproteinemia may influence the lipoprotein(a) level, too.
 ...
PMID:Physiological and clinical importance of lipoprotein(a). 215 33

The plasma concentration of human lipoprotein(a) [Lp(a)] is correlated with the risk of heart disease. A distinct feature of the Lp(a) particle is the apolipoprotein (a) [apo(a)], which is associated with apoB-100, the main protein component of low-density lipoprotein. We now report that apo(a), which has extensive homology to plasminogen, binds to immobilized fibronectin. The binding of Lp(a) was localized to the C-terminal heparin-binding domain of fibronectin. Incubation of Lp(a) with fibronectin resulted in fragmentation of fibronectin. The cleavage pattern, as visualized by gel electrophoresis and immunoblotting, was reproducibly obtained with Lp(a) purified from five different individuals and was distinct from that obtained upon proteolysis of fibronectin by plasmin or kallikrein. The use of synthetic peptide substrates demonstrated that the amino acid specificity for Lp(a) was arginine rather than lysine. The proteolytic activity of Lp(a) was localized to apo(a) and experiments with inhibitors indicated that the proteolytic activity was of serine proteinase-type.
 ...
PMID:Lipoprotein(a) binds to fibronectin and has serine proteinase activity capable of cleaving it. 253 57

Lipoprotein(a) (Lp[a]) represents a class of plasma lipoprotein particles that have overall characteristics similar to low-density lipoproteins but distinct from them by having apolipoprotein B100 linked to apolipoprotein(a) by disulfide bridge(s). This protein has recently been shown to have a striking amino acid sequence homology with plasminogen, a serine protease zymogen that on activation to plasmin promotes the conversion of fibrinogen to fibrin. The high incidence of Lp(a) in the plasma of patients with cardiovascular disease has been noted by many investigators. The new knowledge being rapidly acquired on the structure of Lp(a) should facilitate the understanding of the mechanism of its atherogenicity and perhaps shed light on its possible physiologic role.
 ...
PMID:Lipoprotein(a). A potential bridge between the fields of atherosclerosis and thrombosis. 297 66