What is Bovine Thrombin

Thrombin, synthesized in the liver as prothrombin, is a serine protease that plays a key role in the coagulation of blood. Blood clotting is nature’s way of preventing blood loss.  When body tissues are damaged, bleeding is stopped by a complex clotting cascade involving several proteins, collectively known as thromboplastin.  Bovine prothrombin is converted to its active form, bovine thrombin, in the presence of calcium and vitamin K.   The clotting cascade is a complex biochemical reaction, within which bovine thrombin acts as a serine protease, converting soluble fibrinogen into insoluble strands of fibrin.1

A very simplified clotting cascade, illustrated below, will appear similar to the following: 

Prothrombin + Thromboplastin, Ca++, Phospholipids, & Other Factors --> Thrombin

Fibrinogen + Thrombin --> Fibrin

Uses of Bovine Thrombin

The primary use for Bovine Thrombin is for the defibrination of plasma to produce serum matrices to be used as controls and standards.  

Other applications include:

  • Bovine thrombin is useful as a cleaving agent for proteins and antibody production.

  • As a coagulation protein, bovine thrombin may be used for various clotting studies.

  • Bovine thrombin may be used in protein restructuring  to manufacture food products, transforming meat from lower value  cuts  and trimmings into products of higher value.2

Measuring Bovine Thrombin Activity: IU and NIH units

Historically, there were two standards for measuring thrombin activity:  the International Standard (IU) and the US (NIH) units.  Following a collaborative study in 2003, the units were standardized and the International Standard was established.  While previous lots of thrombin standard material often differed in their IU/NIH units, for the current World Health Organization Lot K Thrombin Standard, Today, 1 IU is equal to 1 NIH.3

RMBIO manufactures standard Bovine Thrombin with an activity of 50,000-150,000 units per gram of powder from USDA-approved bovine plasma sourced from Australia, New Zealand and the United States.  Clotting activity of Thrombin is determined by direct comparison to the NIH Lot K Thrombin Standard using a Fibrometer.4  Bovine thrombin is provided as a lyophilized powder packaged in containers of 250,000 (250KU) or 1,000,000 units (MU). Standard grade Thrombin can be further processed chromatographically to yield purified Thrombin.


Store bovine thrombin products frozen at or below -10°C and avoid repeated freeze-thaw cycles which can negatively affect bovine thrombin activity.  RMBIO manufactures bovine thrombin, thromboplastin, fibrinogen, and various other coagulation factors for use in research and diagnostics.  RMBIO products are intended for research use or further manufacture only and are not for use in human therapeutic applications.  

  1. Thiagarajan, P, and Narayanan, AS(Jul 2014) Thrombin. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1002/9780470015902.a0001410.pub3]

  2. cmsa-ascv.ca/documents/1999July-99Bolespgs12-14.pdf

  3.  “A reunification of the US (“NIH”) and International Unit into a single standard for Thrombin,” Longstaff et al, ThrombHaemost 2005, 93:261

  4. Human Blood Coagulation. Haemostasis and Thrombosis (1976) p. 721-722, 2nd ed., R. Biggs, ed., Blackwell Scientific Publications, Philadelphia, PA