Thrombin

Thrombin (fibrinogenasethrombasethromboforttopicalthrombin-Ctropostasinactivated blood-coagulation factor IIblood-coagulation factor IIafactor IIaE thrombinbeta-thrombingamma-thrombin) is a serine protease, an enzyme that, in humans, is encoded by the F2 gene. During the clotting processprothrombin (coagulation factor II) is proteolytically cleaved by the prothrombinase enzyme complex to form thrombin. Thrombin in turn acts as a serine protease that converts soluble fibrinogen into insoluble strands of fibrin, as well as catalyzing many other coagulation-related reactions.

  • Royle NJ, Irwin DM, Koschinsky ML, MacGillivray RT, Hamerton JL (May 1987). “Human genes encoding prothrombin and ceruloplasmin map to 11p11-q12 and 3q21-24, respectively”. Somatic Cell and Molecular Genetics13 (3): 285–92. doi:10.1007/BF01535211PMID 3474786S2CID 45686258.
  • Degen SJ, Davie EW (September 1987). “Nucleotide sequence of the gene for human prothrombin”. Biochemistry26 (19): 6165–77. doi:10.1021/bi00393a033PMID 2825773.

History

After the description of fibrinogen and fibrin, Alexander Schmidt hypothesised the existence of an enzyme that converts fibrinogen into fibrin in 1872.

  • Schmidt A (1872). “Neue Untersuchungen ueber die Fasserstoffesgerinnung”. Pflügers Archiv für die gesamte Physiologie6: 413–538. doi:10.1007/BF01612263S2CID 37273997.

Prothrombin was discovered by Pekelharing in 1894.

  • Kaushansky K, Lichtman M, Prchal J, Levi M, Press O, Burns L, Caligiuri M (2015). Williams Hematology. McGraw-Hill. p. 1918. ISBN 9780071833011.
  • Quick AJ (1957). Hemorrhagic Diseases. Philadelphia: Lea and Febiger. pp. 451–490. OCLC 599096191.
  • Morawitz P (1905). “Die Chemie der Blutgerinnung”. Ergeb Physiol4: 307–422. doi:10.1007/BF02321003S2CID 84003009.

Physiology

Synthesis

Thrombin is produced by the enzymatic cleavage of two sites on prothrombin by activated Factor X (Xa). The activity of factor Xa is greatly enhanced by binding to activated Factor V (Va), termed the prothrombinase complex. Prothrombin is produced in the liver and is co-translationally modified in a vitamin K-dependent reaction that converts 10-12 glutamic acids in the N terminus of the molecule to gamma-carboxyglutamic acid (Gla). In the presence of calcium, the Gla residues promote the binding of prothrombin to phospholipid bilayers. Deficiency of vitamin K or administration of the anticoagulant warfarin inhibits the production of gamma-carboxyglutamic acid residues, slowing the activation of the coagulation cascade.

In human adults, the normal blood level of antithrombin activity has been measured to be around 1.1 units/mL. Newborn levels of thrombin steadily increase after birth to reach normal adult levels, from a level of around 0.5 units/mL 1 day after birth, to a level of around 0.9 units/mL after 6 months of life.

Mechanism of action

In the blood coagulation pathway, thrombin acts to convert factor XI to XIa, VIII to VIIIa, V to Va, fibrinogen to fibrin, and XIII to XIIIa. In the conversion of fibrinogen into fibrin, thrombin catalyzes the cleavage of fibrinopeptides A and B from the respective  and  chains of fibrinogen to form fibrin monomers.

Factor XIIIa is a transglutaminase that catalyzes the formation of covalent bonds between lysine and glutamine residues in fibrin. The covalent bonds increase the stability of the fibrin clot. Thrombin interacts with thrombomodulin.

As part of its activity in the coagulation cascade, thrombin also promotes platelet activation and aggregation via activation of protease-activated receptors on the cell membrane of the platelet.

Negative feedback

Thrombin bound to thrombomodulin activates protein C, an inhibitor of the coagulation cascade. The activation of protein C is greatly enhanced following the binding of thrombin to thrombomodulin, an integral membrane protein expressed by endothelial cells. Activated protein C inactivates factors Va and VIIIa. Binding of activated protein C to protein S leads to a modest increase in its activity. Thrombin is also inactivated by antithrombin, a serine protease inhibitor.

Structure

Anchoring of bovine prothrombin
to the membrane through its 
Gla domain.PDB1nl2​; Huang M, Rigby
AC, Morelli X, Grant MA, Huang G, Furie B,
Seaton B, Furie BC (September 2003).
“Structural basis of membrane binding
by Gla domains of vitamin K-dependent
proteins”. Nature Structural Biology. 10 (9): 751–6. doi:10.1038/nsb971
PMID 12923575S2CID 7751100.

The molecular weight of prothrombin is approximately 72,000 Da. The catalytic domain is released from prothrombin fragment 1.2 to create the active enzyme thrombin, which has a molecular weight of 36,000 Da. Structurally, it is a member of the large PA clan of proteases.

Prothrombin is composed of four domains; an N-terminal Gla domain, two kringle domains and a C-terminal trypsin-like serine protease domain. Factor Xa with factor V as a cofactor leads to cleavage of the Gla and two Kringle domains (forming together a fragment called fragment 1.2) and leave thrombin, consisting solely of the serine protease domain.

As is the case for all serine proteasesprothrombin is converted to active thrombin by proteolysis of an internal peptide bond, exposing a new N-terminal Ile-NH3. The historic model of activation of serine proteases involves insertion of this newly formed N-terminus of the heavy chain into the β-barrel promoting the correct conformation of the catalytic residues. Contrary to crystal structures of active thrombin, hydrogen-deuterium exchange mass spectrometry studies indicate that this N-terminal Ile-NH3 does not become inserted into the β-barrel in the apo form of thrombin. However, binding of the active fragment of thrombomodulin appears to allosterically promote the active conformation of thrombin by inserting this N-terminal region.

Gene

There are an estimated 30 people in the world that have been diagnosed with the congenital form of Factor II deficiency, which should not be confused with the prothrombin G20210A mutation, which is also called the factor II mutation. Prothrombin G20210A is congenital.

Prothrombin G20210A is not usually accompanied by other factor mutations (i.e., the most common is factor V Leiden). The gene may be inherited heterozygous (1 pair), or much more rarely, homozygous (2 pairs), and is not related to gender or blood type. Homozygous mutations increase the risk of thrombosis more than heterozygous mutations, but the relative increased risk is not well documented. Other potential risks for thrombosis, such as oral contraceptives may be additive. The previously reported relationship of inflammatory bowel disease (i.e., Crohn’s disease or ulcerative colitis) and prothrombin G20210A or factor V Leiden mutation have been contradicted by research.

Role in disease

Activation of prothrombin is crucial in physiological and pathological coagulation. Various rare diseases involving prothrombin have been described (e.g., hypoprothrombinemia). Anti-prothrombin antibodies in autoimmune disease may be a factor in the formation of the lupus anticoagulant (also known as antiphospholipid syndrome). Hyperprothrombinemia can be caused by the G20210A mutation.

Thrombin, a potent vasoconstrictor and mitogen, is implicated as a major factor in vasospasm following subarachnoid hemorrhage. Blood from a ruptured cerebral aneurysm clots around a cerebral artery, releasing thrombin. This can induce an acute and prolonged narrowing of the blood vessel, potentially resulting in cerebral ischemia and infarction (stroke).

Beyond its key role in the dynamic process of thrombus formation, thrombin has a pronounced pro-inflammatory character, which may influence the onset and progression of atherosclerosis. Acting via its specific cell membrane receptors (protease activated receptors: PAR-1, PAR-3 and PAR-4), which are abundantly expressed in all arterial vessel wall constituents, thrombin has the potential to exert pro-atherogenic actions such as inflammation, leukocyte recruitment into the atherosclerotic plaque, enhanced oxidative stress, migration and proliferation of vascular smooth muscle cells, apoptosis and angiogenesis.

Thrombin is implicated in the physiology of blood clots. Its presence indicates the existence of a clot. In 2013 a system for detecting the presence of thrombin was developed in mice. It combines peptide-coated iron oxide attached to “reporter chemicals”. When a peptide binds to a thrombin molecule, the report is released and appears in the urine where it can be detected. Human testing has not been conducted.

Applications

Research tool

Due to its high proteolytic specificity, thrombin is a valuable biochemical tool. The thrombin cleavage site (Leu-Val-Pro-Arg-Gly-Ser) is commonly included in linker regions of recombinant fusion protein constructs. Following purification of the fusion protein, thrombin can be used to selectively cleave between the arginine and glycine residues of the cleavage site, effectively removing the purification tag from the protein of interest with a high degree of specificity.

Medicine and surgery

Prothrombin complex concentrate and fresh frozen plasma are prothrombin-rich coagulation factor preparations that can be used to correct deficiencies (usually due to medication) of prothrombin. Indications include intractable bleeding due to warfarin.

Manipulation of prothrombin is central to the mode of action of most anticoagulantsWarfarin and related drugs inhibit vitamin K-dependent carboxylation of several coagulation factors, including prothrombin. Heparin increases the affinity of antithrombin to thrombin (as well as factor Xa). The direct thrombin inhibitors, a newer class of medication, directly inhibit thrombin by binding to its active site.

Recombinant thrombin is available as a powder for reconstitution into aqueous solution. It can be applied topically during surgery, as an aid to hemostasis. It can be useful for controlling minor bleeding from capillaries and small venules, but ineffective and not indicated for massive or brisk arterial bleeding.

  • Chapman WC, Singla N, Genyk Y, McNeil JW, Renkens KL, Reynolds TC, Murphy A, Weaver FA (August 2007). “A phase 3, randomized, double-blind comparative study of the efficacy and safety of topical recombinant human thrombin and bovine thrombin in surgical hemostasis”. Journal of the American College of Surgeons205 (2): 256–65. doi:10.1016/j.jamcollsurg.2007.03.020PMID 17660072.
  • Singla NK, Ballard JL, Moneta G, Randleman CD, Renkens KL, Alexander WA (July 2009). “A phase 3b, open-label, single-group immunogenicity and safety study of topical recombinant thrombin in surgical hemostasis”. Journal of the American College of Surgeons209 (1): 68–74. doi:10.1016/j.jamcollsurg.2009.03.016PMID 19651065.
  • Greenhalgh DG, Gamelli RL, Collins J, Sood R, Mozingo DW, Gray TE, Alexander WA (2009). “Recombinant thrombin: safety and immunogenicity in burn wound excision and grafting”. Journal of Burn Care & Research30 (3): 371–9. doi:10.1097/BCR.0b013e3181a28979PMID 19349898S2CID 3678462.

Food production

Thrombin, combined with fibrinogen, is sold under the brand name Fibrimex for use as a binding agent for meat. Both proteins in Fibrimex derives from porcine or bovine blood. According to the manufacturer it can be used to produce new kinds of mixed meats (for example combining beef and fish seamlessly). The manufacturer also states that it can be used to combine whole muscle meat, form and portion these, thus cutting down on production costs without a loss in quality.

General secretary Jan Bertoft of Swedish Consumers’ Association has stated that “there is danger of misleading the consumers since there is no way to tell this reconstituted meat from real meat”.

Gold sodium thiomalate

Sodium aurothiomalate (INN, known in the United States as gold sodium thiomalate) is a gold compound that is used for its immunosuppressive anti-rheumatic effects. Along with an orally-administered gold salt, auranofin, it is one of only two gold compounds currently employed in modern medicine. Its precise mechanism of action is unknown but is known that it inhibits the synthesis of prostaglandins. It also modulates phagocytic cells and inhibits class II major histocompatibility complex-peptide interactions. It is also known that it inhibits the following enzymes:

See also

References

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  2. GRCm38: Ensembl release 89: ENSMUSG00000027249 – Ensembl, May 2017
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  4. “Mouse PubMed Reference:”National Center for Biotechnology Information, U.S. National Library of Medicine.
  5. Royle NJ, Irwin DM, Koschinsky ML, MacGillivray RT, Hamerton JL (May 1987). “Human genes encoding prothrombin and ceruloplasmin map to 11p11-q12 and 3q21-24, respectively”. Somatic Cell and Molecular Genetics13 (3): 285–92. doi:10.1007/BF01535211PMID 3474786S2CID 45686258.
  6. Degen SJ, Davie EW (September 1987). “Nucleotide sequence of the gene for human prothrombin”. Biochemistry26 (19): 6165–77. doi:10.1021/bi00393a033PMID 2825773.
  7. Schmidt A (1872). “Neue Untersuchungen ueber die Fasserstoffesgerinnung”. Pflügers Archiv für die gesamte Physiologie6: 413–538. doi:10.1007/BF01612263S2CID 37273997.
  8. Kaushansky K, Lichtman M, Prchal J, Levi M, Press O, Burns L, Caligiuri M (2015). Williams Hematology. McGraw-Hill. p. 1918. ISBN 9780071833011.
  9. Quick AJ (1957). Hemorrhagic Diseases. Philadelphia: Lea and Febiger. pp. 451–490. OCLC 599096191.
  10. Morawitz P (1905). “Die Chemie der Blutgerinnung”. Ergeb Physiol4: 307–422. doi:10.1007/BF02321003S2CID 84003009.
  11. Knorre DG, Kudryashova NV, Godovikova TS (October 2009). “Chemical and functional aspects of posttranslational modification of proteins”Acta Naturae1 (3): 29–51. doi:10.32607/20758251-2009-1-3-29-51PMC 3347534PMID 22649613.
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  13. Wolberg AS (September 2012). “Determinants of fibrin formation, structure, and function”. Curr Opin Hematol19 (5): 349–56. doi:10.1097/MOH.0b013e32835673c2PMID 22759629S2CID 11358104.
  14. Bajzar L, Morser J, Nesheim M (July 1996). “TAFI, or plasma procarboxypeptidase B, couples the coagulation and fibrinolytic cascades through the thrombin-thrombomodulin complex”The Journal of Biological Chemistry271 (28): 16603–8. doi:10.1074/jbc.271.28.16603PMID 8663147.
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  16. PDB1nl2​; Huang M, Rigby AC, Morelli X, Grant MA, Huang G, Furie B, Seaton B, Furie BC (September 2003). “Structural basis of membrane binding by Gla domains of vitamin K-dependent proteins”. Nature Structural Biology10 (9): 751–6. doi:10.1038/nsb971PMID 12923575S2CID 7751100.
  17. Davie EW, Kulman JD (April 2006). “An overview of the structure and function of thrombin”. Seminars in Thrombosis and Hemostasis32 (Suppl 1): 3–15. doi:10.1055/s-2006-939550PMID 16673262S2CID 36616995.
  18. Huber R, Bode W (1978-03-01). “Structural basis of the activation and action of trypsin”. Accounts of Chemical Research11 (3): 114–122. doi:10.1021/ar50123a006ISSN 0001-4842.
  19. Handley LD, Treuheit NA, Venkatesh VJ, Komives EA (November 2015). “Thrombomodulin Binding Selects the Catalytically Active Form of Thrombin”Biochemistry54 (43): 6650–8. doi:10.1021/acs.biochem.5b00825PMC 4697735PMID 26468766.
  20. Degen SJ, McDowell SA, Sparks LM, Scharrer I (February 1995). “Prothrombin Frankfurt: a dysfunctional prothrombin characterized by substitution of Glu-466 by Ala”. Thrombosis and Haemostasis73 (2): 203–9. doi:10.1055/s-0038-1653751PMID 7792730S2CID 20144699.
  21. Varga EA, Moll S (July 2004). “Cardiology patient pages. Prothrombin 20210 mutation (factor II mutation)”Circulation110 (3): e15–8. doi:10.1161/01.CIR.0000135582.53444.87PMID 15262854.
  22. Bernstein CN, Sargent M, Vos HL, Rosendaal FR (February 2007). “Mutations in clotting factors and inflammatory bowel disease”. The American Journal of Gastroenterology102 (2): 338–43. doi:10.1111/j.1572-0241.2006.00974.xPMID 17156138S2CID 19895315.
  23. Borissoff JI, Spronk HM, Heeneman S, ten Cate H (June 2009). “Is thrombin a key player in the ‘coagulation-atherogenesis’ maze?”Cardiovascular Research82 (3): 392–403. doi:10.1093/cvr/cvp066PMID 19228706.
  24. Borissoff JI, Heeneman S, Kilinç E, Kassák P, Van Oerle R, Winckers K, Govers-Riemslag JW, Hamulyák K, Hackeng TM, Daemen MJ, ten Cate H, Spronk HM (August 2010). “Early atherosclerosis exhibits an enhanced procoagulant state”Circulation122 (8): 821–30. doi:10.1161/CIRCULATIONAHA.109.907121PMID 20697022.
  25. Borissoff JI, Spronk HM, ten Cate H (May 2011). “The hemostatic system as a modulator of atherosclerosis”. The New England Journal of Medicine364 (18): 1746–60. doi:10.1056/NEJMra1011670PMID 21542745.
  26. Economist (2013-11-05). “Nanomedicine: Particle physiology”The Economist. Retrieved 2013-12-15.
  27. Chapman WC, Singla N, Genyk Y, McNeil JW, Renkens KL, Reynolds TC, Murphy A, Weaver FA (August 2007). “A phase 3, randomized, double-blind comparative study of the efficacy and safety of topical recombinant human thrombin and bovine thrombin in surgical hemostasis”. Journal of the American College of Surgeons205 (2): 256–65. doi:10.1016/j.jamcollsurg.2007.03.020PMID 17660072.
  28. Singla NK, Ballard JL, Moneta G, Randleman CD, Renkens KL, Alexander WA (July 2009). “A phase 3b, open-label, single-group immunogenicity and safety study of topical recombinant thrombin in surgical hemostasis”. Journal of the American College of Surgeons209 (1): 68–74. doi:10.1016/j.jamcollsurg.2009.03.016PMID 19651065.
  29. Greenhalgh DG, Gamelli RL, Collins J, Sood R, Mozingo DW, Gray TE, Alexander WA (2009). “Recombinant thrombin: safety and immunogenicity in burn wound excision and grafting”. Journal of Burn Care & Research30 (3): 371–9. doi:10.1097/BCR.0b013e3181a28979PMID 19349898S2CID 3678462.
  30. “Sverige röstade ja till köttklister” [Sweden voted in favor of the meat paste] (in Swedish). Dagens Nyheter. 2010-02-09. Retrieved 2010-10-17.
  31. “Welcome to Fibrimex”Fibrimex website. Sonac. Retrieved 2019-02-28.

Further reading

External links

Coagulation cascade
Autoantigens
Antihemorrhagics (B02)
Endopeptidasesserine proteases/serine endopeptidases (EC 3.4.21)
Enzymes

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