Biology:Ecarin

From HandWiki

Ecarin is an enzyme[1] that is derived from the venom of the Indian saw-scaled viper, Echis carinatus,[2] It is the primary reagent in the Ecarin clotting time test.

The venom of the saw-scaled viper, Echis carinatus, causes bleeding and eventually death. The venom contains a metalloprotease called ecarin that converts prothrombin to meizothrombin, a thrombin analog with increased esterase activity, and not to normal thrombin.[3] Ecarin is a glycoprotein with unique metalloproteinase properties. It has a molecular weight of 56,000 and has been found to specifically activate only prothrombin due to its strict substrate specificity. To better understand the structure-function relationships of Ecarin, researchers need to know its primary structure. This understanding is crucial for gaining insight into the related functions of the glycoprotein. To compare the covalent structures of Ecarin and RVV-X, researchers have determined the complete cDNA sequence and translated protein sequence of Ecarin.[4]

Determining the activity of the protein Ecarina is an important step in comprehending its role in initiating blood clotting. To accomplish this, researchers use a special substance called a chromogenic thrombin substrate, which is a molecule that can be cleaved by thrombin, a protein that is a critical player in the blood clotting cascade. The cleavage products that are generated by the substrate can be measured over time, and this parameter can be used to determine the activity of Ecarina.[5]

The activity of Ecarina is usually compared between different types of Ecarin. Ecarin is a purified protein that is obtained from the venom of Echis carinatus. Ecarin is known to activate prothrombin, another protein that is a critical component of the blood clotting cascade. Therefore, measuring the activity of Ecarina is essential in understanding how it participates in the regulation of blood clotting.[5]

In a recent study, the activation of human prothrombin and human prothrombin-2 was compared using two different Ecarin preparations. The chromogenic test was used at pH 8, which is an optimal pH for the activation of prothrombin. The results of this study provide valuable insights into the mechanism of blood clotting and could have implications for the development of new therapies for bleeding disorders or thrombotic diseases.[5]

Ecarin-based assays are tests that have the prospect to be clinically helpful in detecting vitamin K deficiency and lupus anticoagulant. The Ecarin clotting time (ECT) is a test that is widely used for lupus anticoagulant testing in certain regions. Dabigatran etexilate is a direct oral thrombin inhibitor that has been approved as a substitute for warfarin in preventing stroke in patients with nonvalvular atrial fibrillation. It is also used to treat deep venous thrombosis and pulmonary embolism, and to reduce the risk of recurrence. Ecarin-based testing is used to monitor dabigatran, with both clot-based and chromogenic-based methods available.[6]

In 2015, it was reported that 30% of oral anticoagulants prescribed for Medicare patients in the United States were direct oral anticoagulants (DOACs), with dabigatran being a popular choice among cardiologists and internal medicine physicians. This is largely due to the drug's safety and efficacy. It has been shown to be effective in preventing stroke and systemic embolism, and has a lower risk of bleeding compared to warfarin. However, it is important to note that monitoring the effects of dabigatran can be challenging, as traditional coagulation tests such as the prothrombin time (PT) and activated partial thromboplastin time (aPTT) are not sensitive to the drug's effects. This is where Ecarin-based testing comes in, as it provides a more accurate measure of dabigatran's anticoagulant effect.[6]

When performing Ecarin clotting testing, it's important to be aware of the two types of testing available: clot formation and chromogenic analysis. Both methods have their advantages and disadvantages, and choosing the appropriate method can help ensure accurate results.

One essential consideration when determining a testing technique is the effect of a patient's prothrombin and fibrinogen levels. If these levels are low, it can result in prolonged clotting times, which can impact the precision of the results obtained through the clot formation method. However, the Ecarin chromogenic assay eliminates the effect of low prothrombin levels by diluting the sample in prothrombin buffer. It also does not rely on fibrinogen conversion, meaning that it is not affected by low fibrinogen levels. As a result, the Ecarin chromogenic assay is often believed to be a more reliable choice.

the Ecarin clotting time technique can still be useful in certain cases. For example, in situations where the patient has high levels of heparin, which can interfere with the chromogenic assay, the clot formation method may be more appropriate. However, in most cases, the chromogenic assay is the preferred method due to its greater accuracy and reliability.[6]

In determination, when conducting Ecarin clotting testing, it's important to understand the key differences between the two available methods and choose the appropriate method based on the patient's individual circumstances. By doing so, you can help ensure that you obtain accurate and reliable results that can aid in the diagnosis and treatment of various medical disorders.[6]

Ecarin is a highly versatile drug compound that finds extensive use in blood clotting experiments. It is an invaluable tool for monitoring and treating a range of diseases, including but not limited to cancer, liver diseases, lupus, and cardiovascular disorders.[7] Its multifaceted properties make it a go-to solution for healthcare professionals seeking effective and reliable treatment options for their patients.

References

  1. "Monitoring of recombinant hirudin: assessment of a plasma-based ecarin clotting time assay". Thromb. Res. 86 (5): 373–83. June 1997. doi:10.1016/S0049-3848(97)00082-0. PMID 9211628. 
  2. ecarin at the US National Library of Medicine Medical Subject Headings (MeSH)
  3. Paine, Mark J. I.; Laing, Gavin D. (2013-01-01), Rawlings, Neil D.; Salvesen, Guy, eds., "Chapter 240 - Ecarin", Handbook of Proteolytic Enzymes (Third Edition) (Academic Press): pp. 1064–1067, doi:10.1016/b978-0-12-382219-2.00240-4, ISBN 978-0-12-382219-2, https://www.sciencedirect.com/science/article/pii/B9780123822192002404, retrieved 2023-10-05 
  4. Nishida, Shinji; Fujita, Taizo; Kohno, Noriatsu; Atoda, Hideko; Morita, Takashi; Takeya, Hiroyuki; Kido, Isao; Paine, Mark J. I. et al. (1995-02-07). "cDNA cloning and deduced amino acid sequence of prothrombin activator (ecarin) from Kenyan Echis carinatus venom" (in en). Biochemistry 34 (5): 1771–1778. doi:10.1021/bi00005a034. ISSN 0006-2960. PMID 7849037. https://pubs.acs.org/doi/abs/10.1021/bi00005a034. 
  5. 5.0 5.1 5.2 Jonebring, Anna; Lange, Ute; Bucha, Elke; Deinum, Johanna; Elg, Margareta; Lövgren, Ann (June 2012). "Expression and characterization of recombinant ecarin". The Protein Journal 31 (5): 353–358. doi:10.1007/s10930-012-9409-6. ISSN 1875-8355. PMID 22528138. 
  6. 6.0 6.1 6.2 6.3 Gosselin, Robert C.; Douxfils, Jonathan (July 2020). "Ecarin based coagulation testing" (in en). American Journal of Hematology 95 (7): 863–869. doi:10.1002/ajh.25852. ISSN 0361-8609. PMID 32350907. https://onlinelibrary.wiley.com/doi/10.1002/ajh.25852. 
  7. Mohammadi, Nasrin; Bandehpour, Mojgan; Sotoodehnejadnematalahi, Fattah; Kazemi, Bahram (March 2022). "Prokaryotic expression, evaluation, and prediction of the structure and function of the ecarin metalloproteinase domain" (in en). Proteins: Structure, Function, and Bioinformatics 90 (3): 802–809. doi:10.1002/prot.26275. ISSN 0887-3585. PMID 34739152. https://onlinelibrary.wiley.com/doi/10.1002/prot.26275.